I was in this situation recently and here was my summary. The LED has a much clearer viewing window thanks to the need for less tint due to the brighter battery powered dot. The FO version is pretty purple, thus I opted for the battery RMR. It has had a lot of issues with the dot turning off while shooting. One shot it will be on, the next off. A mag later it will come back on, etc. I am told this may be a battery connection and/or seal issue, and some others who have had the same issue reported some success at remedying it by sending it in, or bending the contact/sealing the optic.
Either way, it is an issue that seems to be pretty prevalent on pistols as opposed to rifles (though this could be because RMRs are largely used on pistols rather than rifles. If you intend to use this pistol in a defensive capacity it's something you may want to keep in mind. The trade off is the FO version is sometimes difficult to pickup in low light, so you may have to choose between electrical reliability issues or reticle visibility issues. I will say that when it decides to cooperate it does help for that extra degree of precision. I don't feel that much faster with it, but that's probably because I don't operationally operate enough dynamic high-speed tactical drills, or drive the weapon platform hard enough while sitting on my sofa or whatever. For reference mine is the 6.5 adjustable LED.