We did it for a year and it worked very well. Of course, the friend we lived with was nearly a saint (he put up with me and Mr. Lissar, our loud toddler, me on bedrest, my kid getting diabetes, and a newborn). I put up a thread about it and got lots of discouraging replies. Wise and well-thought-out, but thankfully not prophetic.
We talked about everything, decided the chores/food budget split, and decided that we would be a family for a year. It worked amazingly well. We were fortunate.