I've got a Ryobi grinder, it's actually a very good peice of equipment. Also got quite a few Craftman power tools, never had a problem with any of them, especially the 19.2 cordless drill. It's stronger than any of the other drills I've got, even the corded Milwaukies.
Now if you want really good angle grinder, get a Metabo, best on the market. I've got one, love it.
BTW, just a bit of insider info, Craftman power tools are manufactured by Porter Cable, have been since 1927.