It was very easy, nothing like installing an alternate ROM on a regular Android phone. Mobian was a little better but still had a few quirks.
I made a 24 hours trial using it as my main phone, and had to admit in the end that I would not be able to use on a daily basis. Too many bugs to be usable for me.
I'm pretty sure that this is a great purchase if you consider it for what it is: a development tool. Or a cool toy. I've put it aside for now, but will definitely keep it. Too bad I'm not a developer :)