I always join whichever one has the lowest ping at the time. The downside is that there aren't as many people around, but I want to be able to explore the game as much as I can during the OSWs. I absolutely love it so far. Amazing accomplishment, especially considering that the people working on this are doing it for free, as far as I know.
The only things I saw that I felt could be improved were pretty minor things. I'm pretty sure I first played LoE in 2012, maybe 2013, and the game has come a long way since then.