Yes - I bought a Del-Ton upper assembly for my first AR build. For me, they were great. Very responsive to my numerous questions, fast shipment, and best of all, the upper assembly I bought has worked flawlessly.
I'm working on another project and would use them for it as well - but I'm looking for some specific things that I haven't seen in their inventory (e.g., high end barrel 1:7 stainless, etc).