IMO, it depends on why you want the gun and how you plan to use it, or more specifically, what attributes are most important. I don't own either brand but Spikes and DD both have excellent reputations and DD is supposed to be top notch. Personally, I assembled a DelTon kit (for $600) and it's been 100% to date. If you want an ordinary mil-spec AR or carbine there are many options. Lowers depend almost entirely on parts quality. Assembling uppers involves more skill to get the barrel extension right (headspace) and to align the front sight with the upper. Uppers usually come assembled so you want that done right.