I have been commuting with my D7i since the beginning of the year. I am 6'1" and 215-220 and I mash on it sometimes and it is great. The nexus 7 is great. I rarely use more than 1 or 2 gears on it though. Florida is flat.

Also sheldon brown has great info on maintaining IGH setups. They aren't that hard. Preventative maintenance is best.