That price is pretty high for the DPMS, especially when you can get a superior BCM or Spikes Tactical for about the same. Haven't priced DD in a while but they aren't cheap.
I would put more research into this. DPMS would bother me since they come in dead last out of 14 manufacturers in the "M4 Chart". Even my $800 AR build last summer has five times (16 vs. 3) as many checkmarks on the chart.