Surprised no one has said this yet, but the FFG 12 is not actually an STH series its the z series. So you dont get the sth heel and it uses the standard Z series toe. There ok so long as you dont go to hard on them.
The heel track will break on you if you ride them hard, this was the reason the STH came along, for skiers who needed more then the standard heel piece.
So it depends. If your small, and dont ski too hard they will be fine. If your bigger or skier hard so long as you dont mind replacing the heel track ($10) when it cracks you will be fine. Its a very easy fix btw so not a big issue.