Diving is big business in Sharm, so most operations are pretty commercial!
The major centers are Camel, Emperor, Sinai Divers, Ocean College, Red Sea College and Werner Lau. All are professional, have high standards and use their own boats. They're all based in and around the Naama Bay area, and most have other branchs slightly out of town.
Sharks Bay Umbi is up near the airport and is a bit 'away from it all', it's friendly and relaxed, and they have their own jetty and boats.
Most of the diving here is done from day boats. There are loads of smaller dive centers, some are practically one man bands. With these you're more likely to be sharing the boat with other dive operators and their guests.
Almost every hotel has a dive center on site, so it might be worth seeing who is operating it. On the other hand, all of the big centers will pick-up and return you to your hotel for free.
Depends on where you're staying really, and what diving you want to do.