It's extremely comfortable as long as the position is upright and I'm not working too hard. It rewards gentle, low rpm riding. Trying to spin much beyond about 80 rpm results in all sorts of odd gyrations, and trying to go too fast results in glute cramps, at least for me.
So I guess it's about ideal for a truly relaxed touring bike, which is exactly what I use it for - I keep a good birding binocular in one of the saddlebags and remember to stop as often as possible. But I'm glad it's not my only bike, because the saddle does limit its usefulness - let's just say it's not my first choice for a five hour century.