There are a lot of grips. I like the Hogue, it is cheap, it feels good and fits me well. I like it a lot. But I don't use my AR for hours and hours. Otherwise, I might consider a different grip.
Grips are a personal thing, what works for one person doesn't for another.
The A1 and A2 grips are suppose to be the all-purpose, serve-all, fit-all grips.
There are some things to consider. Some grips do not mate to the lower in an ideal fashion. This causes surfaces to not be flush. That can be either from poor manufacturing to poor design. That can cause blisters or soreness on hands if this rifle is to be held, fired and used for prolonged hours (like a class or something). Also, the gap underneath the trigger guard is an area where some people get a sore middle finger. There are some grips that cover this area, as well as the seam at the rear of the grip between the lower and where an A2 grip would mate.
So beyond what fits well, there's other things to consider - like long term or heavy use comfort. Holding a grip for a few minutes only tells you if it fits your hand, but it doesn't tell you if it will tear up your fingers or fatigue your hand after hours upon hours.