Any opinions on this upper? Other alternatives?

Link

Specs:

   Barrel: 10.5" 4140 Black Nitride Coated Chrome Moly Steel w/ 1:7 twist
   Complete Milspec Bolt Carrier Group w/9310 Steel Bolt - MP Tested & Marked
   Milspec 7075 Aluminum Upper Receiver w/ DSG Logo Engraved
   Seekins Low Profile Adjustable Gas Block w/ Carbine Length gas system
   Seekins 10" MCSR Rail

I bought one and sold it before having a chance to shoot it. I didn't like the handguard, too wide. otherwise it looked good, They were selling complete kits minus the lower for $100 more.
Mine was the 16" version.

don't forget to check the EE for great upper deals.

Same. I held the upper and the handguard wasn't as slim as i'd like. The pictures looked good but when I handled it, I sold it without firing it as well.

It's a good quality upper assembly--certainly worth the price.  But as others have said, the MCSR handguard is fairly fat.  That's for a reason, though--the tube is large enough to let some suppressors fit inside it.  That, and the adjustable gas block, make it a good option if you're considering a can.
The handguard is also fairly comfortable, I should add.  No sharp corners or need for rail covers.  I will say, however, that I'm not a huge keymod fan.  Not that they don't work, but there are limited accessories, and they tend to be expensive.

The crappy cell phone pic below shows this upper (in 16", of course) on a rifle I just gave my brother-in-law 2 weeks ago.  I installed a couple short rail sections on the MCSR to give him a little more flexibility.
The rifle was certainly not "high-end" (not a Noveske or Larue or KAC), but all good quality and it ran like a champ.  I adjusted the gas, sighted it in with the BUIS and the little Leupold, and handed it over.  They put about 300 rds through it and had a blast.  Brass landed in a neat pile about 5 ft away at 4 o'clock, and my niece (first time on anything other than a .22) was bouncing tin cans like a champ.
I did not shoot it for groups, I'm afraid, but I'd say it's probably close to an MOA gun (not sub-MOA, maybe, but certainly less than 2 MOA).

I've got a 16'', also unfired. I thought the complete was a real good buy for $400.

I bought the 300 black out upper last year, the day I recived it I ordered it in .556. I love them! I have the sig brace on a black rain lower. Its my favorite AR. In fact I submitted a form one to SBR it the other day.

I love this setup, it will be a kick ass SBR. I have a saker 7.62 on it.

Barrel is the weak point.  If you can get over that, very nice upper.

I have the 16" version. Shoots as good as any of my other carbines.

4140 isn't top of the line, but at least it's nitrided. Doubt I'll burn it out any time soon, if ever.

As mentioned, the rail is a bit on the chunky side, but the dang thing is really lightweight.

For $399 I really can't complain.

Thanks guys.

I got both the 16" and 10.5" build kits in hand.  Very nice fit/finish. I have experience with a fatter rail, so I was expecting that. Its a very nice rail.

Thanks for the pics, my pending SW762 will look good on there Already slapped a gas buster in it and will be trying the "gas vent" as well. Its a nice addition that it comes with an adjustable gas block. Its no syrac, but for this price, ill deal with it.

The cost of these uppers/kits (at sale price) are pretty nice IMO. I snagged the 16" to give the old man for Xmas, he will get a kick out of it (he has 0 AR)