Well, a *secure* voice server is the most important requirement. I doubt lag will be an issue if it's maintained by PCG (though you never know), but it is very important that we are abke to restrict access to the Eve section to corp members only. Right now it doesn't matter much, but as soon as we get into pvp, wars etc (ie. as soon as we have a reasonable number of members), it will become essential - and having to completely redo our entire infrastructure (voice, forums, etc) again later on would be a pain.
So, if the PCG server can be setup to allow that, then great (also - will it mean we'd have to share the command channel with people playing WoW, Alien Swarm, etc? Or do they not use it?), but if not, then we will need to find something else.