I use TRX stuff a lot and think it's excellent. You can do a wide variety of exercises, balanced. Body position affects "weight". SImple, effective.
I use it as part of a "boot camp" type of training group I'm in 2-3 times per week. I really enjoy it, and generally don't like indoor workouts. If the coaches are good - well trained and savvy to individual limitations and modifications, and are good at avoiding injuries by their students - its an excellent full body program. Much better than what I've been doing the past few years: XC skiing and basic core training in the winter, bicycle, hiking and core training in the summer. The boot camp stuff is much better -and I still ride and ski, much stronger with both.