I had both done at the same time. It was a major turn on for both myself and hubby but I had nothing but trouble with them from the start and after two years took them out.
I found that for a couple of weeks they would be fine...then I would have two or three weeks of agony and soreness. Then they would heal again and the cycle continued.
I finally gave up, even though it pained me to do so, and took them out.
Whilst they were in an 'ok' period I found the nipples to be ultrasensitive which was brilliant but couldn't stand the other times when I would freeze as soon as hubby came near me!
I would really love to try again. Maybe this time I will go for the one at a time theory.
As with everything else, piercing is a personal preference. I for one can't stand faces full of metal but find nipple piercing highly erotic....*shrug*. Each to his/her own!