I started out in 1979 carrying a model 36 in a Desantis ankle holster. I later carried a Detonics 45, a 2 1/2" 66 and a 3913 until my knees started giving me trouble. I returned to a J frame, but in an aluminum alloy frame in a Fobus holster.

All the horror stories of loosing guns from ankle holsters are usually the result of poor quality or ill fitting holsters. I found that lace up uniform boots were the most comfortable way to carry a BUG in uniform. For off duty or plan clothes I found ankle high lace up hiking boots like Merrells are comfortable when the ankle holster rides on top of the shoe.

It's been my experience that you usually see trouble coming and have a moment or so to prepare. Drawing from an ankle holster certainly telegraphs your move, but I found that by stepping forward with the gun bearing ankle and kneeling on the other leg, I could draw and fire faster than someone carrying in a fanny pack that was so popular with LE in the 90's.

As mentioned in other responses, it's easy to draw from an ankle holster when seated, such as driving or in a restaurant. While ankle holsters are not the be all, end all answer to concealed carry, they do provide you with additional choices. Most anyone who tells you that ankle holsters have no place in CC has either not had a quality holster or has never actually used one for any period of time to get use to it.