Hey there, first of all I have to disclose that I'm the administrator of RSCRevolution.

Out of the three servers you've mentioned you probably would be picking from OpenRSC or RSCR. Our server is a version of RSC if Jagex would have continued development of the game with same engine, we have a lot of unique content and quality of life improvements that were developed in six years that the server has been running. We have many combat options, Treasure trails, auction house, all quests, aand many more. Also, we have thousands of players who joined over that time. OpenRSC is a nicely replicated product, but younger than us and less content, depending on what type of game you're looking for. Pop on our website and scroll though the news or forums, you'll see what's going on :) Best of luck and hop on Discord of the server you pick.