I had a hard time deciding on which shop to have install my Ford Racing 4.10 gears (just a couple of months ago). Talked with people at a few shops --- wound up going with the guy at a local dealership (because he had the most experience and knowledge).
It was a bit expensive, but the job was done to my FULL SATISFACTION. No vibration and no "gear whine". Runs just as smooth and quiet as the factory installed 3.27 gears. I quickly forgot about the extra $$ for the install.