If looking for PCB fabs, I find this a useful site, written by one of the folks on the eevblog forum.
I've put a lot of prototype runs through over the last year, my experience has been at the low cost 2-layer 6/6 track/space >= 0.4mm drill, it's rare to get a board that's not pretty good. Sometimes the silk screen is better registered than others, but no big deal. So just pick the price to arrival time tradeoff that's acceptable.
As you move up in cost, I'm yet to have a PCB fab who hasn't stuffed up one of my orders. Highly inconvenient, but at the end of the day it's how the fab responds to feedback about their processes and corrects the situation. In that I've been quite impressed with Easyeda, very responsive and quickly replaced an order that wasn't acceptable without a week denials and blaming everyone else in the process.