About 90% of the racers around here run hydraulic oil.Have personally ran it for years and would put nothing else in my pg.Trans runs cooler and since using my stock planataries last two to three times longer and my car has 1.20 60s and weighs 2800#.You will have to explain to me how oil changed your stall it never effected mine.Most aftermarket tranny fluids also contain hydraulic oil.
I used to work in the air compressor field. When rotary screw compressors first came out they could be run with either ATF or 10wt or 20 wt hydraulic oil. I don't think there is much difference between the base stocks of those oils. Probably the biggest difference is the detergent adders in ATF. Just my $.02.