I have a JD40 and a Poker X, and I much prefer the JD40. The build quality on mine is amazing, and the switches feel great (lubed 65g MX black). Mine was built by JD, but I'm sure CtrlAlt is doing a great job with the ones they are making.
I find the JD40 more useful than the Poker, due to the full programmability (example, I have a numpad on mine, which I prefer over the Pokers number row). The JD40 can do anything you could ask a keyboard to do. It takes a little while to get used to the layout, but it only took a couple days. I barely have to move my hands to type either, as everything is right under my fingertips. It is now my daily driver. It's also beautiful to look at.

Really my only nitpick is with the enter key, as it's 1.75x. It's a little tougher to get keycaps for it, because you need two caps lock keys and sets generally only come with one, although JD40 kits are becoming pretty common in group buys. I don't mind the feel of the smaller enter.
I do like my Poker X as well though, both are nice choices.