I just yesterday picked up my 2002 TJ from Letzroll in Mesa Az. Among other things I had them install a Ford 8.8 with new gears, locker, bearings, calipers, rotors, pads, brackets - basically a rebuilt axle with good used shafts. I haven't gone off roading yet so I have no input there, but the reason why I had it done after 3+ years of research was that I started the project, looked at the cost of doing it myself vs. having an expert shop do it for me and the difference was minimal enough for me to have it done and have peace of mind.
Long story longer, I also had them install chromoly shafts in the front, locker and re-gear, upgraded tie rod and drag link, custom aluminum lower control arms, all to run 35's. I bought the best parts and had the best people work on my TJ because only want to pay for this once.