I'd like to share my positive experience with Andy Kim. My Ortofon A90 was in need of a retip/rebuild as it had developed a noisy channel. Ortofon does offer a "rebuild/exchange" program but that was more money than I wished to spend, plus I was interested in the sound of this cartridge with a different stylus profile. I chose Andy as the rebuilder as he's here in California and offers a quick turnaround, plus his reviews were excellent.
Andy discovered damage to the Replicant 100 stylus plus a tweaked cantilever. His replacement cantilever has a micro-ridge stylus. He also reconditioned the suspension, straightened the remaining cantilever, and cleaned the cartridge internals.
The cartridge was back in my hands in a few days and, while it's impossible to compare this rebuilt cart with it's new self, it sounds top-notch. I've very pleased and it was much easier to dial in - Andy suggested 2.0 grams with a level headshell - bingo. On top of that I saved ~$1500 compared to a factory exchange.
I highly recommend Andy Kim's cartridge services.