If Factions retains the FPE's armor skin system, I'd have to go with Kurzicks while shopping because I like most of their armor skins more than the Luxon counterparts. And no, I don't care if something is popular so long as I think it looks good--did I stop wearing 15k Glads just because it's popular? Nope!
Henchmen-wise, I like the Luxon set more. On the Kurzick side, Gai-sensei, Danika, and the other monk did a fine job healing, but Luxons have Kai Ying the handy Earth ward-bishie who keeps squishies alive, Talon Silverwing the squawkin' Tengu warrior, and Daeman, a better interrupter than Eyrs Vasburg. That and the Kurzicks use Rot Wallows...boo!

During FPE, PvP-wise, it was very Luxon-heavy early on, but Kurzicks ended up winning much more. I'm probably going to choose Luxons just because I like Siege Turtles more~
Also, the wide-open Luxon Jade Sea (at least the limited range we had access to) was very relaxing to navigate through and permitted mob-dodging (although the scenary gets boring very fast) whereas the Kurzick forest environment, while EXTREMELY beautiful with superb background music and great atmosphere, had very crowded mobs that reminded me of SF, an overabundance of ranger enemies who spam Spike Traps all over the place, and frequent ambushes--all of which forced me to crush every group I encounter.
So yah, aesthetically, I'd side with the Kurzicks, but practically I'd side with the Luxons. I don't dislike or like one side more than the other, and I don't really care about their ideologies or attitudes, so I choose the side with less-annoying PvE environment. Go turtles!
As a note, I feel that the always-balanced Kurzick strike forces (when I was Luxon) were a better challenge than the specialized Luxon strike forces (when I was Kurzick)...doesn't this somewhat go against the stereotype?
