I just had six states install 5.29 gears in a Toy 3rd that I just bought that had a Detroit and stock gears. The bearings were almost new, so I didn't need an install kit. They charged me $100 for labor and $20 for a new pinion seal. Even though they're packed with the pre-Moab rush, I left it with them for a week and they had it done when they said they would.
I've heard Precision gears are pretty good, probably better than the Genuine Gears I just had them put in, but I got two sets of 5.29's and the third with the Detroit for $500, so I guess I'll see how they hold up. I have Richmonds in the rear of my truck and I think they are the strongest, but that's just my opinion.