Where I am, Costco does a good job - clean negs, no scratches.
However, they're not without their limitations - in particular with "pro" films, if you're getting them to scan/print, you may not be happy with the results - the operators may not be familiar with the films' characteristics and you may not get exactly what you're hoping for. For instance, last year I was in a hurry and had them process/print/scan a roll of Portra VC (colours are supposed to "pop") - the prints/scans came back with neutral colour (actually, as the machine was a Noritsu, I think they may have applied the settings for Portra NC by mistake). Now, for my purposes with that roll that was OK, but it may not be what you're looking for. Now I've bought a scanner so I can scan my own negatives at home, so I just get them to do develop-only, and it's all good