I really like IDW’s take on Jazz:  he’s every inch the easy, brilliant, kind, dangerous charmer he is in G1, but IDW also gives him an interesting arc as he becomes more disillusioned with Optimus and the war.  The problem is that Jazz gets comparatively little screen time, and so his story tends to get told in dribs and drabs across thirteen years’ worth of comics.

What I’d recommend (roughly in chronological order):

• Infiltration/Escalation/Devastation/Revelation:  I’m a bit torn on this recommendation; it’s our first introduction to Jazz in IDW, but he doesn’t appear that much in these series.  His appearances are gold, though (includes him fervently thanking their new human friends for pointing out that the Autobots’ holoform drivers all have the same kind of uncanny-valley little half-smile and it’s really fucking creepy :D).
• Spotlight:  Jazz:  Absolutely a must.  Jazz at his cool, badass best.  It’s also kind of fascinating as one of the only Spotlights – possibly the only other one being Spotlight:  Drift – that’s actually told mostly from another character’s perspective about the title character.
• All Hail Megatron:  Again, Jazz’s role is brief here, but it’s important nonetheless, and this has some of my favourite Jazz bits in IDW.  This is Jazz the Spec Ops commander, whose reputation alone is enough to terrify bots into submission; it’s also Jazz the Good Boss who stands up for this team even to other Autobots, and Jazz the Caring Friend (his dynamic with Prowl really picks up here).
• The Transformers ongoing series (by Mike Costa, not the later one by John Barber):  I’ll admit, I don’t like these comics.  I am not a fan of the writing.  However, not only do they have a decent amount of Jazz, but what happens to Jazz here is key to understanding what he goes through later.  The Transformers was divided into several arcs which were later published as individual trade paperbacks.  If you’re reading for Jazz, you can basically stick to two arcs:  Revenge of the Decepticons, and Police Action.
• Robots in Disguise/The Transformers (the other one)/Optimus Prime:  Jazz’s major role in this series basically starts right after Dark Cybertron – with the “Earthfall” arc, issue 28.  This is Jazz at his most conflicted and, I think, most interesting, and it’s the first time we really get a substantial look inside his head.  Jazz continues to play a role right up through the end of the series.