I just hope the Worlds Fair 1939 regions can find a new OpenSim home. They were standouts at Reaction Grid. I'm not interested in Unity because I lack the skill to build my own content, and my employer barely rewards my OpenSim work; it counts as an innovative class assignment, not as some cutting-edge part of my annual eval. As with many educators, I find that it's easier and more profitable professionally to author a new article or develop a new class than to learn new and complex content-creation tools.
It's great that Jokay's grid will continue, however! So will my use of that grid.