I think it's tough to say which one is "better" they both go in slightly different directions.
The Decks are no-nonsense boards with great build quality, insane sturdiness and longevity. They also look plain awesome in my book but they don't offer anything like media keys and that sort of thing. Also they are freakin expensive and the company that produces them is basically not doing anything. They don't develop new ****, they don't expand, they don't advance in any way. They are actually receding everywhere, the products and information offered on the deck webpage has reduced constantly over the past years. Nowadays you can order a very limited amount of products on their website and there is close to no information found there. The forum looks like a desert, too. If you contact them u always talk to the same person, Adam and I would wager that there are not many more people working there. Deck might well be a dying company. Might be because they are as self proclaimed "not interested in turning a profit" but just make a kickass keyboard "cuz we can".......
iOne on the other hand is a taiwanese keyboard manufacturer that is making strong pushes on the market and look more like they are just getting started and have plans for their future, which Deck obviously doesn't.
The x-armor u9BL looks sweet, offers lots of good features and at a nice price. But it is way too early to comment on it because there aren't any facts on how good the key printing method they use actually is. It could be a total flop (as many expect, rubber coating has never been a good call thus far) or it could be a genius new way of printing keycaps (as many hope but few believe).
So which one is "better" ? No idea, wait for the x-armor u9bl to be established and have been used for half a year or year by some people, then see their reviews particularly on key wear.
If someone would want to gift me one of the two I would choose the Deck, hands down. It's just more valuable right now and the keys are one of a kind. In the future this might become even more true if Deck should really die as I suspect.