Between going from an IBA to an IOTV, and back to an IBA for the time being, I have to say I really prefer the IOTV now. The suspension system is a subtle improvement you don't notice until it's gone, as is the over-the-head donning style for me personally. My old IBA was great on my '05 deployment, but then we didn't have to wear the neck collar, groin protector, or the DAPS. We do now, and it sucks in every way imaginable, but thats an organizational thing so ces't la vie.
Since I am a HMMWV gunner on a convoy escort team, I don't wear any pouches at all on the vest (again organizational) save for the IFAK, so I can't say what it's like on the IOTV. I will say though that being 6'4", even the XL IOTV only covered me about to the bottom of my rib cage. Great for mobility, not so much for catastrophic abdominal wounds. Yes, the cvilian at Ft Hood told me not to worry, it fits fine!
The glaring problem I have had with it is the quick release, in that about every third time I go put the vest on it falls apart. Great idea, poor execution. The cable keeps coming out of the loops in the back and voila, falls to my feet in so many pieces. Aggravating, but an added PCC now that I expect it helps out. I thought it may have been operator error since I am Infantry, but a few other guys in the Plt have the same problem. Other than that, it could be a bit lighter and less bulky, but the suspension setup and adjustment straps are a step in the right direction.