I've a Jungle Gym, which is like a TRX. I actually prefer it to the TRX and it is half the price

I am allowed to do chin-ups (palms facing me) with bands occasionally and they are much easier than pull-ups (palms away). I've a recalcitrant shoulder problem that IS slowly improving We do have to be very careful with it however. I hope to someday be able to do chin-ups without assistance.