I ordered a Colt 6920 Magpul Black from IRunGuns and a Daniel Defence M4V7 from Wolverine 2 weeks ago, and I now have both in my hot little hands. Both are excellent. With the furniture being the difference. Both sport the "keyhole" mark noting that both upper and lower recievers were made in the same place anyway..... So that left internals as the major difference. And really... I can't tell the difference myself between the 2, I'm a first timer too. The DD trigger has some grit feeling too it, but that's it. Little different styles, but both go boom really well. I prefer the Magpul furniture setup better I suppose compaired to the long tube on the DD.... But thats personal preference.
Honestly, if I was buying again now, I would get the Bushmaster deal from IRunGuns. 625 for an AR? You cannot go wrong. Bushmaster has a very good name as well.
Otherwise, both dealer companies had excellent service, Wolverine being a bit more personal, because it's smaller, but IRunGuns were great as well and very quick. I ordered it on the 14th and it showed up on the 1st. I can't complain about that!