The consensus from CoS is Arachnaea, since PvPers seem to want to gather on Dragonfall.
And you believe they will stay after a PVP server opens?
As of 1:40 pm (EST), only two servers were up - Dragonfall and Arachnaea. The other ones spotted last night are not on the list - it's possible they were additional servers being prepped to handle increased beta-testers later in the weekend event in case these two get filled to capacity. So it will look like there will just be two availiable for this weekend at the 12(3 EST) launch for the first Closed Beta. I'll keep my eye out for others opening up.
Since there are just two now, and next wave PvPers will be able to test their own server (I'll be giving it a go for a bit myself, to see how unrestrained PvP works. It's been a while since a game I've played has had it) I'll put my vote for Arachnaea. It's population should remain stable in the coming weeks (it won't lose as much to the PvP server opening) and those who want to test PvP can get their chance next beta event. Right now I'm nore concerned about testing the features availaible, and getting my feet wet in the game. :) At 2:45 (EST) I'll see if any of the other three servers were opened up, and tally up the votes people put out to see which server we'd like to try out as our 'official beta rp server'.
There will only be 2 servers for this event weekend. I would suggest Arachnaea, though I will be trying both servers personally.