You are right, there is only a branch of Israel's "Aqua Sport" club in Taba. More than enough for this small strip of land.
Taba offers some nice sites in comparison to Eilat, so if you don't have much time to spend in order to travel farther from Taba it is cool and nice enough. However, it is not among the most famous sites in Sinai.
There are several nice sites close to Taba, some accessible by boat (through Aqua Sport) and some by Land. My favorite site in the area are Ras Mamlach and Ras Abu Galum. However, they are beteen Nuweiba and Dahab so diving there from Taba requires a long day if you want to enjoy the place. There are other nice dive sites accessible from the land like the "Fiord" and the nearby "SunPool" just a few minutes driving from Taba.
You may consider also diving in Eilat, there are some nice sites a few minutes from Taba, just see my previous message in this thread.
Dangers? Most probably desert-related: Heat stroke and dehydration so don't forget your sun-blocking lotion, hat and drink a lot. Second danger is probably car accident especially if you use Egyptian taxi drivers. I can't figure out any other potential dangers, except some diseases you may get in some "health clubs", if you know what I mean...
