Quick thread revival because people tend to start these types of threads and then never share which product they decide to buy. I ended up purchasing the MagPul Pro LR BUIS. I went with the LRs because they were only a few dollars more and I thought they look better. Plus I might run a .22 conversion and the dial on the rear sight would allow a quick adjustment for rim fire. My local shop carries the MagPuls in stock. I went ahead and ordered and installed a Blitzkreig front sight post. The sights are very nice.
Yesterday I ran across a lightly used Vortex Sparc AR for the right price. I might go ahead and pop it on the gun. Or just toss it in a drawer for the next gun. Maybe that can be the topic of another thread.
Out of those two, I say go with Magpul. You can find used ones and you won't be out much money, especially if you are going to put an optic on it in the future.