08+ have the 6 speed and a little more power. more technology / refinement
03-07 have the better interior IMO

IIRC GM did not introduce blue tooth into their truck line until 2011-2012? my previous truck was a LTZ tahoe with nav and all the newer technology. it was much more refined i do miss some of the small add ons that my older H2 doesnt have. the interior was built more strongly and wouldn't break as easily as the hummers. the seats held up way better to. that being said my next truck is gonna be either 08-09 H2. comparing the 2 i feel like i went back into the 80s when i switched to my 03 H2.

if you like the older interior find a 06-07. if your willing to spend a little extra and get the 08-09 i would hold out for it.

 

Not to nitpick, but the 2009 models had bluetooth. 2008s and earlier did not.
2009 Bluetooth Upgrade in a 2008 H2 ? - Hummer Forums by Elcova

A lot of the "new" tech in vehicles is easily recreated with current double din nav units. The only downside I see in comparing the H2 to newer SUVs is the inclusion of larger screens that sit higher, where the vents are currently.


Interestingly, you can put the 08/09 seats in the 03-07 models.
Actually, I need to make a thread about that... it's a curious thing.

 

I did the bluetooth upgrade in my 08, well worth the time. I also did the lockpic so I could add extra cameras etc.

 

Almost got this, still thinking about it:
2008 HUMMER H2 SUV Chicago IL 13047286