Bottom-line is 'it depends.' I've got about 50 dives in with Cruz Bay Watersports and about the same with Low Key, and got my Rescue Diver certification w/ Low Key in 2008.
Cruz Bay Watersports (known for their red shirts, decent boat, and arrogant attitude of their towelboys on the island) is a huge operation that is primarily based at the Westin Hotel in Chocolate Hole. The dive boat, as of Spring 2008, operates from a dock at that hotel. They see significant turnover in their staff, reportedly because the organization doesn't treat their staff very well. Consequently most of their staff appears to have the attitude that they have better things to do. However, if you're going to the island, don't mind strictly 'beginner' dives, and are staying at the Westin - ask for Charlie... he'll take care of you.
Low Key is based in Cruz Bay and their attitude is extremely 'low key.' Their ops director, Ellen W. was fantastic to work with, and gave us a great deal on a package dive. (In fairness - they all do that) but LK was more communicative. They also seem like more of a 'family' - including the irrascible owner of the company. They actually did take us on an 'advanced dive' (it was truly hard core) and took us most of the way around the island to an amazing site another day and didn't treat us like children or tourists. Further, their dive shop is right near 'The Beach Bar,' a great place for a post-dive burger and beer (and live music later at night). Their gear is on par with CBW but the staff appears to be much happier and that atmosphere makes the dives much more enjoyable.
I have never gone on a Chris Sawyer dive, all I can say is that it appears to be a much more bare-bones operation.
