I carried a steel J-frame Smith in a Galco ankle glove for years, and have carried a Glock Model 26 in a DeSantis (Apache?) rig for about 3 years, since my agency outlawed revolvers. There are a lot of cheap, rotten ankle rigs out there, and carrying with a bad one is near impossible. The Galco rig had a leather holster attached to a wide neoprene band which worked great with the J-Frame, but when I tried the same model for the Glock, I couldn't get my pants leg over it. The DeSantis rig is like another model called the Renegade, which uses a big elastic band to secure the pistol, in lieu of a leather holster. IMHO the most important thing to look for in an ankle rig is the big neoprene (think wet suit) band and a big sheepskin pad behind the holster. The holster's are a bit pricey ($75+), but it pays off in the long run. I think I spent more than that just finding one that would work.
Incidentally, the draw we teach is to drop to the knee on the off-holster leg, which draws the pants leg up on the holster leg and allows quick access, firing from the kneeling position, which is pretty stable. Anyone else use a different draw?