I had my ears pierced twice many years ago when I was in grade 6 or so. I had nothing but problems with them and took them out. They were done with a gun, and it's a terrible way to get piercings in my experience. I don't know any professional piercers that would ever use a gun. All my piercings have been done freehand with hollow needles, and I would never use another method.
I had my tongue done when I was 20. I didn't care for the placement, it is far too close to the front. And pain does not BEGIN to describe the feeling of having it done. I was in agony the entire time, and he was not quick about it. He actually had to back the needle off halfway through and slam it through again. Yeah, so ouch. That was 6 years ago. My current piercers said it shouldn't have hurt like that. I've taken friends to get theirs done, and they haven't experienced that level of pain, so I think the guy that did my just sucked. I had to switch to a tilatnium barbell, as the stainless wasn't healing quite right.
I then had my horizontal eyebrow done at a place in windsor. Quick, easy, painless. Healed fabulous until I ripped it with a towel and had to remove it. I only used seasalt and water to clean it (and all subsequent piercings). I was told not to use any petroleum based products as they trap bacteria inside the wound and cause abscesses. And that has been my experience whenever I tried it. I had my nose and labret done at a different place in windsor, and it was another bad experience. I almost ripped the arms off of his chair I was in so much pain, he was very very slwo and since he was older, hands weren't as steady as I would have liked.
My nose healed eventually, though I had a lot of problems with a keloid (I also have a nose screw, and would use nothing else). My lip I couldn't keep clean enough due to my job, so I had to remove it.
I went back to the first guy and had my lip redone after I switched jobs. No problems healing it at all. Then I went to him again and had my bellybutton and horizontal eyebrow redone. Once again, quick, painless, clean and easy (and Sean is HOT). I did get keloids on both, but that's just my screwed up body. Both healed fine. I ended up ripping the eyebrow again, and gave up on it altogether.
Then I got hit in the face by a dog (I was a groomer) and ripped my lip open, split my gum and had to remove the labret.
I went and had it done AGAIN, and it healed fine. I also had my lobes done with an 8 ga needle at the same time. I took the labret out a year or so later to get a vertical put it, but never did get it (my piercer talking me out of it, the jerk).
I stretched my lobes to a 4, and they healed fine (it was very painful, though, like a bad burn). But I do get gunk behind my tunnels, but I don't think you can avoid that really.
I would like to get more, but I feel I'm too old. I'm almost 26, and to me piercings seem like a 18-20 year old thing to get. Plus, I get keloids on all my piercings now, which I HATE as they are such a pain to get rid of. So now I just have my tongue, bellybutton, ears and nose.