The only ankle holster I like is the Desantis Apache holster. They are sewed to fit the specific models of guns and the gun pocket is heavy elastic type material. I've carried Glock 26, S&W 642's and several different pocket type .380s in them with excellent results.
When I first started carrying ankle I tried just about every brand, even Alessi (spelling?) which was hot back in those days and I always went back to the cheaper Apaches.
Good luck!