I've had mine for almost 3 years, and I (mostly) love them. Sometimes I get tired of always having perky looking nipples under thin clothes lol or catching them on things.
Mine didn't hurt much at all. No eye watering even! I do have a fairly high pain tolerance though. But, they didn't hurt as much as my nose, madonna or.. other places >.> haha
I know quite a few girls who have had theirs done and none of them have had any problems with sensitivity after they've taken them out. I have yet to do so with mine, so I can't really say. Mine are definitely more sensitive, which is good and bad. Good, because it's fun but bad because sometimes my boyfriend can't be as rough with them as he'd like.
The most important thing you can do for them is make sure they are healed really well before you change jewelry or do any rough play.
People will tell you all kinds of crap, like they're be fully healed in a month, or that they will never heal. All the bad stuff people say usually comes done to two things, either the piercer sucks and didn't do it right, or the person didn't take care of them. Just listen to your body. Make sure you get jewelry that fits right. I've had to change the lengths of my barbells a couple times over the last 3 years because of my weight changing.
Also, sports bras will be your best friend for at least a few weeks. I slept in a tight cami and it really helped. Shot glasses worked best for me for cleaning them. Zap a shot glass full of saline for 4 seconds in the microwave, and stick the shot glass in your sports bra so you don't have to hold it lol
No regrets, they're still probably my favorite piercing =)
My boobies look so naked to me without them!