[HummerJim]

I have the air suspension on my H2 and love it. I offroad every time I go out, since I live in a wooded area that you can only access down a dirt/mud and gravel trail and through a small creek. Emergency responders have warned their equipment might not get through in an emergency and my homeowners rates reflect that, but I love where I live and if it wasn't for 4 X 4s it would be impossible to live here full time.
I always keep the rear aired up since coming down the hill makes scraping the spare a real possibility. I'm not sure what the speed is, but I think it's around 40mph where it squats back down. I haven't had any problems with the bags or the sensors either. I also carry a Sears 12v compressor in the bed (it's much faster than the Hummer unit) but I've used the Hummer compressor on numerous occassions. Having two compressors makes airing up much faster. I have a battery in the bed too in parallel with the front battery that I can disconnect with one of those green twist off switches. I love my H2 and the air suspension.