I really liked the improvements made from the 05 base rockhopper which I own to the 06 base model which my roomate purchased this year. The SRAM components are much better IMO at that price point, as is the front fork and wheelset. The geometry is the same (awesome for me) but the upgraded components really make the bike feel better in most riding conditions.
I'm not familiar with the component spec. on the comp models so I can't really help you there.