BT- has the loosest fit and the lowest front cut; but it probably also translates into the quickest draw. It also wears out your slide finish.
AA - has a tight-fit and not sure whether it will loosen over time; has the highest front cut. Has a suede lining that minimizes wear on slide finish; it's also the reason why it has a tight fit.
STC - has a relatively custom fit, which has less lateral room; the front cut is between BT and AA. The lining is made out of leather that is bonded to a kydex shell. It is definitely the best looking and fabrication of the three. Of course, it's also the most expensive.
How do these compare with the Bladetech, as far as usage goes? I just picked up the Bladetech, but I sure would like something with a softer lining.