Glock 22 - $325 (PD trade-ins)
Several to choose from. One in particular looked like new.
Ed's in Stockbridge (770-474-6084)
http://www.edspublicsafety.com/
I'll agree with you there brother. Your experience with DPMS is a testament to the quality of the AR/M4 in general and specifically to that brand. My 15 year old's build is a Anderson/PSA and it works fine. Cost around $500 with spare parts we already had.
I'm sure it's fine for the average shooter who'll hardly use it. As for the difference, quality of materials and features. We all know that most M4 fans want after-market parts. Might as well do the math and buy a rifle that someone has already set up the way you like or has parts you can...