YHM makes pretty good products for the price. They have a pretty good reputation for value for the dollar. Their AR's look pretty good, and the diamond fluting is definitely sharp. They have lots of YHM features and accessories for the price. I've seen them discounted at gun shows so you might save some dough if you find one at a local gun show.
They have both 1:9 and 1:7 twists. If you plan to shoot the heavier 75 or 77 grain bullets, you probably want the 1:7.
If you buy one, just check the staking on the carrier key and you're probably good to go.
Look at the hot new Daniel Defense M4 carbines. They are a little more than the YHM rifles, but have heavier duty Daniel Defense accessories. They have milspec features like their barrels. Impressive first offerings from Daniel Defense.
I've also seen some MP 15T's from SW discounted into that price range at gun shows. The SW has a Troy rail and Troy back up iron sights which are a nice accessories.
Colt 6920's without the railed handguards are also coming back down in price and they are the real deal milspec wise, except for the 16" barrel for civilians versus the military's 14.5 inch barrel and full auto selector.
I've held the YHM models, and they seem put together well and the price was definitely reasonable for the included options. I always look around in the same price range to see what other brands have also, but you're a good shopper and probably have already had your hands on some of these.