Re: what is a comfortable boat to be on for a long time
I don't think Hartley18 was being the least bit harsh on the fellow. In fact, his answer was spot on. Some people can live quite comfortably on tiny little boats. I once spent a month living on a 23' trailer-sailer, and it wasn't too bad. On the other hand, there are those who would feel claustrophobic on a 50' catamaran--which has, after all, considerably less living space than most small apartments.
What's going to be "comfortable" is a completely subjective and personal thing, that no one else can tell you.
Best advice is probably to look around at a number of different boats, spend some time below in the living spaces, and decide for yourself whether or not it seems like it would be "comfortable" for you.