Your mileage may vary! I found it easy and rewarding, other people find the ortholinear layout confusing and struggle to type on it, as some sibling comments show.

The one hitch I hit early on, is that it turns out I type 'y' with the left finger on laptops, and on a stock ErgoDox, that involves hitting a layer button, which of course throws off one's rhythm. I had to turn that key into a dead key until I got used to typing y with my right finger (I still hit it with the left on a laptop).