Not totally sure. I've been verbally pummelled by a trans* acquaintance when they asked me this question and I froze. They took a "..." for a "no" and proof of my not-transness.
In my dreams I'm always a man, I see and feel myself as a man so I think that waking up biologically man would be like driving on an empty highway versus being stuck in city traffic.
On the other hand I'm not cool with the beard and loosing my voice range, and given that I'm a passive gay I don't find anything too bad in having an extra option. I would do without periods and breasts and a slightly deeper voice tho.
Also I want to know: do I get to wake up taller? More muscular? Because if I wake up with a Y chromosome and a beer belly on my compact frame, I take objection.