OK now that i had time to play with my @nitrokey here's a more balanced "review":
As mentioned, it works really bad as a "drop-in-replacement" for an old rsa4096 key (5-6s).
But it is amazing for a new ed25519 key (0.2s).
Very happy i bought it, but now i have to deal with replacing my pgp/ssh-pub-key.
Still having trouble using it with OpenKeyChain on Android...
So the nitrokey does not support openkeychain (gpg on android).
With the latest firmware (1.5.0) even *trying* to use it renders the key unusable (until you unblock the pin on the computer).
Seems like i'm not replacing my old yubikey anytime soon, but looking forward to the fixes.
At least they seem to be working on a patch...
Felix