The H2 is just too big...and is a true symbol of "American Arrogance". However, to be fair, the H2 does off-road well...the huge tires, skidplates, rear locker WITH ATRAC up front (excellent combo!), and impressive angles (approach, breakover, & departure) alone make a good off-roader off the showroom floor.
Is the H2 reliable?? Well, it is based on the Tahoe's old platform...so, it should be decent. Is the suspension up to task?? Well, the tie rod is kinda weak for the H2 size/weight. But, if you're careful, then the H2 is pretty good (for it's size). Is it the best for it's size?? No, i think that the Dodge PowerWagon is better.
As for the H3, i do think that it is quite impressive in it's class. I would get it over an H2 in a heartbeat. It has similar advantages as H2 (listed above), but it comes in a smaller package with a tremendous transfer case (optional). With the H3, you actually get a much better interior (quality-wise) than the H2. The interior & exterior panel gaps are smaller in H3...it seems like GM designed the H3 better than H2. The H2 seems like a last minute glue & tape job by GM engineers. GM seemed to put more thought and effort into creating the H3 from the Colorado chassis.
My only gripes about H3 are:
1. It's a HUMMER...therefore, some people may vandalize your truck or flip you off!
2. Kinda space INefficient...a lot of wasted space due to design.
3. Weak engine power...not good if you do a lot of highway driving.
4. Small windows...impossible to back up!
5. Questionable reliability/durability because of it's roots (GM).
6. Suspension & drivetrain components are not tested yet...still too new. Hopefully, it is more "over-engineered" than the H2.
7. Lastly, ATRAC (traction control) shuts OFF in front when you lock the rear axle. This sucks the big one!
My opinion.