I'm new to building an AR--I've been looking at the various options and am wondering if there's anything inherently questionable about buying an upper that includes a lower parts kit, such as this one:

http://www.midwayusa.com/product/891...ProductFinding

not saying this is the one i'm looking at per se, but simply is this the better way to go, or do most people prefer to buy a preferred upper, and then just a parts kit separately.

the reviews of the DelTon upper/with parts kits on midway seem to be pretty solid.