Originally posted by J.W. Blute:
When you mentioned polymer I’m assuming you are talking about the MAGPUL BUIS. I have a set of them and so far I’m happy with the purchase. They work well, seem robust (Granted, I haven’t done any drop tests with my $$$ Bravo Company AR-15) and they are half the price of their machined steel counterparts.
Bravo makes a damn good product....and If Magpul were around when I needed BUIS I wouldn't have hesitated as I've never seen an inferior product from them....
Let us know what you ultimately end up with. Depending upon the optic you wanna run, keep in mind the possible need for a low profile jobber...or just a plain ol cowitness.

Being honest, price was the determining factor for going with MAGPUL. My reasoning was: The primary sight on my rifle is an EOTECH 557. It is a very robust sight (works even if the window gets partially smashed) and I carry spare batteries. The MAGPUL sights are only for back-up if the primary sight goes down. By purchasing a quality optic and preparing properly to keep it running, the chances of them being needed is very small. Thus, why pay top dollar for sights I’m taking great lengths to never need when there is a cheaper alternative from a reputable company that will do the job.