Cat certified mechanics will usually do a "by the numbers" Cat defined survey, Service Report and oil analysis. But that sometimes doesn't tell the whole story and I would prefer a mechanic who does some thinking about what he finds rather than just going through the numbers.
Eric Rydzewski, AKA Ski In NC is such a guy and while his engine base is broad, I understand he has quite a bit of Cat experience. You can PM him on this site.
Another Cat specific guy is Tim Caruso. His website is Contact Us
Eric is near Wilmington, NC and Tim is in SW Florida. Tim in particular flies anywhere for Cat surveys.