I grew 2 from Fast Buds that could not have been more different, one was a short squatty indica and the other was a 10 foot tall sativa amazon that I had to super crop too many times. Both had great yields, close to a LB a plant and the smoke was good but not great and that could be on me. It was a first RDWC grow. Personally I think that was a seed mix up but I also dont think Fast Buds has been in business long enough to have any stable Autos. They got the marketing thing going for sure. 

If your talking about a Nirvana strain I think it would be a much more consistent phenotypes. I could be way off but Glue and Girl Scout Cookies seem a little like the current strain bases like Nourthern Lights and White Widow once were. Anyway if autos are your only choice I would go for it