I very recently had my nipples re pierced. If you do get them pierced.. don't change your mind and take them out. I missed them within months, and after a while I had to get them re pierced. It hurt more the second time, but i'm happier with the alignment. So, I guess it was a good thing in the end.
Oh, and thats something I should mention. Spend ages getting the alignment right. After they mark it, go to a mirror and move your shoulders back, change your stance, do things and look at how it changes the look.. you want to get this done right the first time.
So anyway, getting them re pierced meant going through a some scar tissue which hurt, quite a bit. The PA is a walk in the park compared to nipples (it still hurts, but its easy). Again the placement is a big thing with the PA.. theres a lot of small blood vessels around there, and with good placement.. well, my PA bled twice.. both times just after I showered and my blood was warm.. but the rest of the time it was fine and didn't even sting when peeing.
All in all I'm very happy with them. If you aren't sure you want it done, try to imagine how you would look with body jewellery. You're not just getting this for play purposes.. you have to like the idea of looking like that too.