For competition/target shooting (in the starting at $500 category) you have only two options. I say "starting at" because invariably you'll catch the disease and start making "upgrades"...
I had a Beretta Neos and it was a fine gun. Ate anything. You can shoot steel with it fine. Same goes for the GSG.
But you only have to look at the websites that are geared towards providing parts and accessories for this competitive area to see what everyone is shooting. And that answer is Ruger and Browning.
and then a vendor of their parts:
You notice they don't do parts for much besides Ruger and Browning.