I'd definitely buy PSA before considering DPMS, just based on my own experiences with both. That's not just about DPMS parts being out of spec (which I've encountered a fair number), but also the way they look and feel, a lot of it makes me think of cheap 90's era AR parts. (To be fair I have not worked with the G2, and would consider one of those an exception because I like the concept.)
At least one member here bought a G2 and had horrible results. Over gassed, wouldn't extract.
I'd considered buying one until I saw the threads on his train wreck.....
Perhaps the OP of the G2 thread would be kind enough to post a link to it?