Hard to go wrong with Colt or DD. Like you I'd rather get the 6920 instead of the 6940 though a few people here have the 6940 and say good things. I wouldn't be interested in any Hamster.
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
US Army 1966-69, VFW Life Member, Retired Geek
I just bought a colt 6920...great gun. I was at the store and they had one for a little under 1200 and while I was looking at it I received a call from an acquaintance the wanted to buy mg used 6920 for 1600 so I bought the new one. Wut a day! Lol all in all the colt 6920 is a damn good rifle. And around here 223 ammo is running bout 9.99 per box of 20 for pmc and 12.99 per 20 of the American eagle ar223 Carnot tipped ammo
If you can get an LE6940 for under $1500 in today's market I would grab it up... If all else fails you can guaranteed sell it for more than you bought it for. I own a LE6940 and it has been an excellent gun for me, the only issue I had was that colts have a sear block in them so most drop in trigger mechanisms won't fit. But I'm upgrading to a LaRue OBR now so it's all good. Good luck on picking.
I bought my Rock River Arms off of Gunbroker.com. Paid 1620.00 including shipping and transfer fee. Super nice gun. It's the ATH Carbine with stainless steel 1:8 match barrel. Here's a few pics. Also found 4 30rd Troy Battlemags for 84.00.
The used 6940 I was looking at Sunday is gone. I like the 6920 better anyway, and the LGS said I could order one, but no guarantees on when it will come in. I don't mind waiting. He quoted me a price of $1200-ish.