I've owned a nostromo for about two years, I find it's shape odd and uncomfortable for overall use. It's not viable for movement in MMO's where I often find myself strafing, circle strafing, or otherwise moving in a complex fashion...

I don't have an x-keys however I've grown VERY used to running my G15 keys without my hand losing track of the home row on the keyboard. My intention is that when I get my x-keys pro to place it directly left of the G15 which means it's just a little farther to have access to more keys. The ones closest to the G15 will be the commonly used, the farther ones will be the less commonly used.

Ultimately it's really pretty easy to find keys on anything that has common breaks like the G15 clusters of keys and I'm assuming the X-Keys layout will lend its self to that sort of blind navigation as well. Of course as with anything, the more you use it, the less you have to look to get to it.