I've ordered from PierceOff many times and have always been incredibly happy with their service and their products.
The first time I ordered from them, I ordered a 14ga SS conebell - the threading on one of the cones was too short and it kept falling off, however after an email to the lovely Felicity I had my replacement on the way, and I had no problems. Even when I ordered a 10ga barbell and couldn't get one of the balls off, all I had to do was send it back and I was sent back a new one with the balls already loosened for me.
I have ordered a variety of jewellery from here - barbells, curved barbells, d-rings, CBRs and have always been happy with what I got. The jewellery is good quality, and the prices are excellent (I got a 10ga barbell for AU$10).
I recently bought some piercing needles from the site and were incredibly impressed by them - it was my first time piercing myself, and the needles were great quality and slid through perfectly - even through my conch.
So all up, Pierceoff is a GREAT place to get jewellery from - I've had nothing but great experiences with them, their customer service is fabulous, and I only buy my jewellery from them now.