I use dvorak and I can agree that there are at least a few popular chords that are inconvenient, like Cx Cf. But I've gotten used to this and haven't changed any core key bindings.

And, of course, the upside is that on any random machine with emacs is 100% compatible.

Oh, and one more tip :-): bind 'vim' to 'emacs -nw -Q' which loads emacs really fast (without requiring the daemon to be running).

I use evil-mode with colemak for insert mode only: https://pastebin.com/raw/Lnf5GL3G

The big problem is that all(?) applications use logical instead of physical keys for hotkeys combinations so any custom layout would break everything.

I do. Since C-x is very common I swapped T with X. Here's the snippet from my init:

    ;; Swap C-t and C-x, so it's easier to type on Dvorak layout
    ;; `keyboard-translate` does not work when attaching an emacsclient to
    ;; a running emacs in daemon mode, so instead we define the key in the
    ;; key-translation-map.
    ;; http://lists.gnu.org/archive/html/help-gnu-emacs/2009-10/msg00505.html
    (define-key key-translation-map [?\C-x] [?\C-t])
    (define-key key-translation-map [?\C-t] [?\C-x])

With this modification I find Emacs with Dvorak very comfortable.

I use emacs with programmer dvorak[0]. I use the default key bindings and it didn't get me too long to adjust. I tried changing the bindings to new locations but they're so many and in the end they're just arbitrary. I've been using that same setup for almost 4 years now and I don't have any intention of changing it :)

[0]: http://www.kaufmann.no/roland/dvorak/

I use emacs with colemak. I find it more ergonomic than emacs with qwerty. Is there anything specific you find cumbersome?

I do. I actually found the defaults to be more comfortable with Dvorak. Which chords feel unintuitive to you?

Happy Colemak user here. I have been using Colemak for two years, and Emacs for a little more than one year.

However I use Spacemacs with Vim keybindings :D

I do, with dvorak. I also map control to alt-gr for the best ergonomics, so all keys have equally easy control combos.