I used my G21 in a club match last weekend. I am using the Aluminator holster I bought from Glk21C along with 3 Safariland 771 pouches on a CR Speed belt. With the Arredondo mag. extensions, it was no problem to plan reloads. We had one 32 round field course that I wound up doing 2 reloads to complete. I didn't do that well though, came in 8th out of 26 in Limited, but that isn't the gun's fault. I'm just a little out of practice. Now if I can just find the time to get in some more practice before next months matches, I know I can do better.
Eventually I will set up my G20 for Limited with a .40 conversion barrel, but I'm having fun shooting the G21 .45 for now. I just love seeing those big .45 holes appear on the target, and it really knocks pepper poppers down with authority!