I haven't done a lot of skiing in SC, so can't comment on ESF / schools. Perhaps someone else might be able to?
Re the transport from Turin, it should take just over an hour from Turn to SC, so the quote seems ludicrous to me. I would definitely hire a car if that is the only other option. Suspect there may be coaches, but wouldn't know where to start. Perhaps you could contact the big companies that fly to Turin and ski at SC and see if they have any space on the coach?
The only think to consider is that you will need snow chains - and the hire charges for those tend to be ridiculous.
We are heading here in Feb half term. Not having much luck finding a ski school for DS apart from ESF. I haven't heard good reports about them and was keen to try and find another school. Anyone know of any?
Also, we are flying into Turin and have been quoted around 550 euros for return transport from the airport!!! We are thinking of hiring a car now but has anyone found a cheaper way to get to SC?