I performed the squat portion of Starting Strength. That is 3x/week, 3x5, increasing weights each time. I went from completely detrained strength training state, from coming off my season, to matching my PR within about 6 weeks. Honestly, it was great at the time. Unfortunately, at the end of that 6 week run I had to get surgery, so I can not ever be completely conclusive of it's GPP effects for the next cycle I planned on starting; however, I was a squatting machine and didn't really have much issues at the time.
It is VERY important to keep up with your rest, kcal intake, and flexibility/mobility. Squatting this frequently, even with dead perfect form, is very hard on your joints and soft tissues. Once you start to get near your maxes (if they are of any decent weight) it will take its toll on you very quickly.