I have a red/green dot Strikefire.
I did a LOT of research into similar sights. I trolled OpticsPlanet and lots of the other reseller sites, reading reviews and doing a shit-ton of price shopping.
I couldn't find a better deal than the Vortex. Includes the doubler for free. I've got mine zero'd in on my AR, and like it for fast follow-up shots. But I'll probably put the M-223 back on it for total accuracy.
I got a saddle mount picatinny rail for my shotgun, and plan to use the Strikefire for deer season too. With rifled slug barrel and good sabot slugs, I'll be a LOT more confident this year. I missed a doe high with three shots last year using open sites. No more.