Should be good. Seekins makes quality parts and DSG is a great vendor. You can't even build an upper with those specs for that price. Theres not a better value out right now IMO.
They come with a Seekins freefloat handguard and adjustable gas block. Both the Spike's and PSA uppers are standard hand guards and front sight base. The Spike's and PSA use FN made barrels which is great. DSG stated that they can't disclose the maker of the barrel on these uppers due to essentially a non disclosure agreement. I have no doubt they are good to go.
BCGs have just about the same specs, c158 bolts and 8620 carriers and hpt tested. Not sure about mpi on the DSG.
It's a 16" barrel and 15" handguard. 1:8 twist is great. You usually find them on precision barrels as they allow for a very wide array of ammo. They are not CHF barrels. They are melonite treated though increasing corrosion resistance and some argue that its better than chrome lining.
The handguard is about $200 usually, gas block is $60, bcg+CH around $100-110. That's like getting a barrel and upper for $30