Here thigh holsters are used by specialized folks. In our city police station, only motorcyclists use them for pistols, although plenty of patrolmen carry Tazers in them, but pistols above in a conventional belt holster. As has been mentioned before, retention is an issue with thigh holsters more than with belt holsters, other factors being given.
While I do confess to owning a thigh holster, it is intended for military use for me, where the bad guys are slightly further away (but just as angry).
Rust and bureaucrats. Freedom and vigilance. Front sight and trigger. Kindness and firepower. Situational awareness and tolerance. Safety and concealment. Taxes and allegiance. Love of man and surgical marksmanship. Once a soldier, always a soldier.