They are both good boards.
The price quality ratio varies a lot depending if you live in the US or in EU.
BTW keep in mind that the U9 plus may be the best deal of any mechanichal keyboard because has an hidden gift.
http://www.overclock.net/keyboards/1031531-my-first-mechanical-keyboard-xarmor-u9-3.html
LMAO that is realllllly strange. No wonder xArmor isn't around anymore
But, I am quite pleased with my U9BLS. The plastic part of the stabilizers are kind of flimsy but it's not really a big deal as long as you are careful when pulling bigger keys. They're actually pretty much on par with everything else that isn't a Filco or Das so whatever.
Haven't touched a cherry board though, so I can't help you there.
edit:
I also think it's worth noting, the keycaps on the U9 are coated with a really smooth material. It took me a bit of getting used to how it feels, but I like it now. At first it was kind of weird though.
Hmm, what else can I say about these boards.. They are quite sexy, so that's a plus. And they sound perfect :]