Fastrack runs trackdays very well. everyone there is good people.
the track is difficult and has its own character. 6th gear down the banking and into T1 in 4th or 5th is something everyone should experience. a few of the other turns are fun too. unfortunately, the asphalt is getting worse and plastic curbs & cones are unnerving. Buttonwillow is a better track for sure, but you will prob still enjoy AutoClub.
AutoClub has free garages with power, which is nice if you are using warmers or its a hot sunny day.