I have not,,, but quickly looking at the specs and a pic of the sight,,, it looks quite a bit more rugged. The Win/Elev adjustments look beefier as well. Everything else looks like added functions or options. (always good) I have no idea. I've haven't had either of my FF's crap out on me,,, but they aren't old, and they are only on rimfire range guns.,,,,, a previous poster states his FF 2 is quite durable,,, and he probably has more time with it than I do. I havn't heard this,,, but an RDS has internal electronic circuits to worry about as well,,, there is more than physical placement on the slide that can get jacked in pretty much any RDS. I would never do it intentionally either,,, and I hope it never happens accidentally,,, but I'd rather know it will live through anything I put it through. I would be VERY surprised if the FF2 on my 22/45 lived if I dropped it sight down. That right there would rule it out for me.... I don't want to "activate" my sight on a CCW weapon,,, or any weapon I used for PP. Not to mention,, if it's on you as a CCW,,, it will get abused a bit more Everyone's different man,,, you gotta make that call for yourself. All I know is,,,, everytime I let the budget dictate my purchase of firearm equipment instead of my research and wants,,, I ended up resenting the fact that I didn't save up a bit longer and pony up the mula the first time. And what are we really talking about here,,, $100 -$150 bucks difference,, it's not much considering you will have $500 - $600 in the gun, $250ish into the milling, a bit more if you want iron sights as well. I saw a LNIB RM05 on AR15 yesterday for $325 shipped. You just can't beat the RMR when you can get them used for that price. I usually end up doing it to my original desires the second time,, and that's WAY more expensive. My RMR experience is no different. I cheaped out,,, resented doing so,,, and went the RMR route,,, cost me a boat load more!