Hi thedon! This is a really cool mix, full of good balance decisions. I love the attitude you've created with your compression settings, and the way you've also thereby created real cohesion without tremendous amounts of reverb -- that's my kind of mixing!
With that in mind, I'm going to give a long list of potential critique points, but I don't want it to take away from the fact that I think this is a really funky mix -- one of the best I've heard so far, in fact, on a sheer gut instinct level. I'm always just of the opinion that it's the criticisms that teach us anything, so I'll now try to give the best educational value I can, if you see what I mean -- apart from anything, given your terrific work in the Discussion Zone over the years giving feedback and encouragement to other forum members, I'm especially keen that you should get maximum value from my feedback! So, here goes...
The overall tonality is good, although there's perhaps a touch of midrange honk in there at around 700Hz. Try cutting a couple of decibels there, with a Q of maybe 1, and see whether that makes the result seem a touch more 'hi'fi'. To be fair, the 700Hz emphasis is great for small-speaker translation (an important point given the mixing brief here), but the downside is that the midrange can somehow cheapen the sonics of full-range playback, so I think I'd play it a little safe on that count given Hannes's jazz leanings (and general penchant for smoother sounds, in the light of the Ben L'oncle Soul reference). The other thing that appeals to me in general is the slightly saturated sound, which is part of what's giving the 'glue' here, I think -- it's a kind of satisfyingly retro furriness and fullness that I can really imagine appealing to the artist, especially if you've had a listen to any John Mayer (which Hannes also referenced).
However, I think part of the saturation (and a less attractive part) is coming from your overdriving the master buss in pursuit of loudness. This is a seriously loud master (louder than the library preview mix, in fact, which is already pretty hot), and given the high level of both lead vocal and bass in your mix, both are generating quite a lot of square-wave-flavoured harmonics. (You're not hard-clipping, but the flavour's there nonetheless.) In combination with your master-buss compression, I think this would be a bridge too far for Hannes, who does like a bit of microdynamics left in the mix (although admittedly less so on this one, given that this was probably the most 'singly' mix on the album). For me, the other problem with the loudness is that it does really soften the attack of your kick hits, so that they have too much of that 'folded in' feeling. Try comparing your mix with the library preview mix, but with both loudness matched, and you'll hear what I mean. As you know, I'm very much a pragmatist when it comes to loudness processing, but I still think you're discarding a little too much punch and rhythmic drive in pursuit of level here.
Moving in to specifics, I do like the bass sound: the way it shares the sub-100Hz region with the kick is well-judged, and its small-speaker translation is also decent. The drums raise a few questions, though. Firstly, there appears to be some kind of phasey sound to the main drum hits that seems a bit out of character with the music, particularly when the sidestick's involved. Have you been time-stretching things to make timing corrections, perhaps? Is there some kind of parallel effect that's not properly latency-compensated? These are both things I'd immediately suspect if I heard those kinds of artefacts. In addition, the snare does feel rather lightweight compared with kick, which is something that isn't a big deal when they're playing together (ie. most of the time), but becomes more of a concern when they don't, for example in the Reintro, Outro, and during some of the fills -- in all of those spots, the groove isn't nearly as effective when the kick outguns the snare.
And speaking of groove, the compression you've applied to the main off-beat rhythm guitar is pulling up the sixteenth-note muted strums, thus emphasising the smaller rhythmic subdivisions and making the rhythm feel a little bogged down -- it's a well-known psychological effect. In Chorus 2, the guitar solo seems to have had a similar kind of processing, although here the problem is more that the tone of the muted picking is rather clicky and distracting, so if you're determined to use that compression there, then I'd consider using an EQ or transient processor to tuck those transients back into a more appropriate balance. One other guitar-related point: is that opening guitar solo just a bit 'stringy'? Somehow it works better for Verse 1 than it does for the Intro. Perhaps you might EQ in a bit more 800Hz only for that opening section. Maybe that's just me, though...
One of your headline additions is the string patch, and I can see the reasoning as far as Verse 2 is concerned, in that you can use it to differentiate Verse 2 from Verse 1. However, for me this is probably the least successful decision in your mix. The first issue is just one of realism -- they sound too obviously like canned MIDI strings, which takes away from the fundamentally 'live band' presentation the band have tried to create here. Admittedly, I'm a string player myself, so perhaps I'm oversensitive to this, but even if these strings were real live players, I think they'd still be inappropriate here, because they add a kind of veneer of large-scale saccharine glossiness that seems at odds with the band's general aesthetic. It's somehow too much 'easy listening' or 'pure pop', rather than 'singer-songwriter crossover', if that makes any sense at all!
I don't question your instinct that the second verse needs something to lift it after the first, but I think you could have fulfilled a similar arrangement role with piano, hammond, or guitar additions (or even effect spins, given the reggae/dub influences), without having to expand the palette outside the range already set by the band themselves. You could even have got away with backing-vocal or electric piano additions, I'd have thought, depending on your own facilities as a performer. In general, though, it's always lowest-risk to expand an instrument part that's already there, rather than adding something new.
But there's another aspect of the strings that I'd query, and that's that they continue to contribute to the arrangement beyond the point where they really need to. For example, there's no real necessity for strings in the choruses, because the Hammond covers that base pretty well already (even if it's not quite as mono-compatible). In fact, the strings actually make the Hammond less audible, which might not endear you to the keyboard player!
It's a fine line, but I think it's always least risky to make the most of the parts that the band have provided before adding anything else of your own.
I like the way the lead vocal cuts through the mix, but I wonder whether you could maybe give it a decibel or two less 2kHz, so that it sounds a little warmer and less nasal. As with many other mixes people have posted, the lead vocal's low-frequency levels aren't all that consistent yet, and could do with some specialist frequency-selective (or manual region-specific EQ) processing to even them out. Check out "smile I see is telling me so" at 1:47, for instance, and notice how the syllables "see is tell" feel much bassier than the others. Even once you've addressed that, though, I reckon you could still put in more detailed vocal rides to maximise the lyric intelligibility, especially in the Choruses, where masking from the backing track is increased. In the Outro, the vocals mix feels very murky, so I'd suggest balancing those parts more in favour of the higher voices, and then applying some careful low midrange EQ cuts to further clarify the texture.
I like a lot of your arrangement moves here, but I'm not sure the drop-down for Verse 3 is operating that well yet. Basically, it just feels like you stay at that dropped-down level for too long. Then you just reintroduce everything you dropped out at the start of Chorus 2, which seems a bit of a missed build-up opportunity. I'd suggest selecting some element that you've dropped, and already introducing that at 1:57. Then adding another of those parts at 2:06. That way, there's a sense of ratcheting up the arrangement towards the Chorus, which should not only keep the listener's interest better, but also create some arrangment momentum through Verse 3. On a much more niggly note, the song's ending fade-out feels a bit ragged too, especially with the Hammond cutting out so abruptly. It just seems a shame to me to leave the listener with a less-than-ideal final impression when you've done so much good work on the mix as a whole.
Finally, I think your stereo width feels rather constricted, despite the added strings element, because mainstream mixes on the whole usually like to make a widescreen impression. I'd suggest panning the solo guitar lines, for instance, and the added advantage there is that they'll conflict a little less with the centrally-panned lead vocal that way. The Hammond and piano tracks are both candidates for MS-style widening processing, as I see it, given that neither is musically essential, so hearing less of them in mono is no great loss. One of my favourite tricks on pop mixes is to widen the bass too, because this gives a lovely warm enveloping feeling to the mix as a whole without recourse to master-buss EQ. In the preview mix I used GVST's freeware GChorus for this, and widened it a touch further with Voxengo's freeware MSED plug-in. (I also high-pass filtered it to avoid any mono-compatibility problems at the low end.) Reverb effects are another candidate for widening processing, especially in this multitrack where the drums room and mob vocals are both be feeding mono ambience into the mix.
I hope some of that proves useful. As I said at the outset, this is a mix that just
feels engaging, and vibe counts for a lot when it comes to winning over clients in my experience. Thanks for letting us all hear it!