I'm from a nearby tribe, and don't really know either of these groups that well. That said, the few times I've wandered through thier area, I've found the Cendres folks to be friendly and approachable.
On the other hand, the guy attacking them here (Laranthalas) is among the most obnoxious people in the local chat, is definitely an unprovoked pk'er type, and also sucks terribly at pvp in general :P
Take from that what you will, I suppose.