DB15, Obsidian vs BCM Blem Upper + PSA Lower

Similar price ranges, having trouble deciding between:

  1. Buying a DB15, 16" Obsidian Series complete riffle
  2. Building one based on a BCM Complete Upper and a PSA Complete Lower

I found a lot of comments/opinions on the BCM/Lower combos, but not a lot comments on the Diamondback obsidian series.