Yeah, the UJs aren't good if you have a plumber crack. They did take a full bladder (about 8 hours is a full bladder for me), while I was laying on my stomach...So in conclusion, they have about two times more absorbency than Pull Ups.
They have more "mature" prints than Pull Ups. To be honest, I wouldn't recommend them for teens or adults.
hahaha.. thanks for the responses- I think I'll stick with Pull-Ups just because I can't find any UnderJams at local stores; I just love the idea of theoretically being able to fit into a non-adult diaper, though. Pull-Ups I can fit into, but I either have to wear them low, which is pretty uncomfortable, or wear two at once, which is extremely comfortable and looks really cute, but takes about 10 minutes to work out.