I had mine fitted at A14 Performance, very reasonably priced and they offer a lifetime guarantee providing you take it back once a year to get your card stamped. However I forgot to take mine but it's been on the car about 4 years now.
As for quality I'm no expert but I wouldn't say they're anywhere near the best but by no means the worst (you get what you pay for I guess), all I know is you tell them exactly what you want and they'll do it, if it not quite right they will sort it for you. I told them what I wanted and pointed out the tip I wanted on the end them came back at the end of the day to pick it up.
I was happy enough - took a few weeks to sound right but after being run in It's just what I wanted.