I'm different also, I don't like the 30 rd mags. The 20's work better for me, they don't get in the way and they dont have the jamming problems like the 30s.
BUT, all my magazines are the military 20's. I do have one USGI 30 round steel mag but don't use it much.
Then again I pretty much only shoot High Power and only load 2 or 8 rounds in each.
I guess how you shoot would determine what you need.
CPT USAR Ret
USAMU Sniper School Oct '78
Distinguished Rifle Badge 1071