I've had both my nipples done my right horizontal and my left both vertical and horizontal. It started with just the vertical left and built from there. Yes it hurts, but if done right it's quick. Healing takes time, but as long as you are diligent it's not a big deal. It does increase sensitivity.
My sister gt her nipples pierced and as soon as she did when she got home she flashed me. She said she liked it a lot. But you also have to have a high pain tolerance I'm guessing. I think they're cool looking and that you should totally do it.
I have my nipple pierced and didn't find it painful at all but that might be due to the fact i asked for it to be numbed beforehand