Changing strings on a slot head guitar isn't as easy as a solid head stock, but I find that is only an issue when I break a string in performance (when time is of the essence).
I play a 000 slot head 12 fret, but I had it built with a 1 11/16" nut. A friend had one built for her that way, too. Peter is correct about them usually coming with a wider neck width.
I find the tone much more balanced than say, a dreadnought, and it is much more comfortable to play with a strap (after playing a dreadnought for 25 years).
I don't miss the extra two frets at all. I still have my dreadnought, but I rarely play it.