I'm also looking at RDS sights myself. Warranty wise, Vortex and Burris, both lifetime, no receipts, no questions asked. The Burris fastfire 4 looks interesting. I have seen a lot of videos of guys going from Trijicon RMR's to Holosun, mostly for larger field of view, and the extra features. The green dot option with multi recital's is high on my list. The only Trijicon I like is the SRO ($$$$). Regardless of what brand, or what price, I want my iron sights as a fail safe.