Personally, I loved them both and will probably play both. The cashing in your points helps with that ability to switch, too; I was really worried about this point until I tried it out.
Both sides had their appeal in their own way. I honestly can't say I found one better than the other.
Which one to play first, now, I'm not sure.

I'll probably wait and see what my guild wants to do. My guild leader seemed to think it was cool that he could ally with one or the other, although he didn't get to contemplate it long before a dragon killed him. I'm leaning a bit towards Kurzicks because I love the gothic look, but the Luxons had a wonderfully bright look to everything that I loved, too.
I honestly don't think you can go wrong choosing either one. Watching the two during the end event was amusing; I was in Cavalon ID1 and House zu Heltzer ID1 at the same time for a bit (until my desktop choked on Cavalon ID1 over remote destop, heh), and it was all different than what I'd have expected. The Kurzick side, portrayed as being a bit stuffy and formal, had people dancing around everywhere, every which way, jumping around, ect. The Luxon side, portrayed as being a bit more lighthearted, had carefully lined up rows of dancers all in sync.
I had a great time playing stuff for both sides, though, and look forward to playing April 27th (go preorder early access, I took two days off of work!).