Hm. Well, first I'd take advantage of the opportunity, give it a test drive (probably a good long one - and no, I'm not talking about sex, I'm talking about social interaction in general - being able to experience something I otherwise wouldn't would be quite interesting for me (although I suppose sex would be a subset of that)), sate my curiosity, and then, assuming I don't come to like it more than being a guy, see what I can do about reversing the process.
Because as interesting, and enjoyable as I might find the experience, on the balance of things I enjoy being a man. I'm used to it - my balance would be different, so I probably wouldn't be able to move quite as effortlessly as I can at present; a lot of the social cues and body language I use wouldn't elicit the same reactions if I were female - Rage, for instance, is (generally speaking) more effective at terminating an unwanted conversation when coming from a tall, strong man than from a tall, strong woman (not that I actually ever get enraged, but I can make people think I am). The reality is that society reacts and shapes the lives and perceptions of men and women differently - and while that makes the theoretical ability to experience the other side of the coin, so to speak, very appealing, in the end I still prefer the circumstances that I have.
In terms of dating, I might enjoy the onus being on the opposite party initiating a relationship, but then, seeing as how I'm not attracted to men, that would probably just become really annoying.
Also, I don't like the idea of having a period. It sounds messy and potentially uncomfortable, for one, and while I don't know a great deal about the effects of hormone-shifts during periods on behaviour and thought, it would certainly be something I wouldn't appreciate - I've put a lot of work into fine-tuning my impulse-control, and I wouldn't appreciate losing that. That said, perhaps it's iron-clad to the point where it'd just be a bit of extra work, rather than actually changing the way I act.
Yeah, looking on this, it seems my sense of self isn't tied inexorably to my gender/sex/whatever - I'm just used to being a guy, and objectively, given my personality, preferences, and the way society reacts to men vs. women, it's probably a better fit for me. But I would theoretically appreciate being able to experience both sides of the coin.
And if it wasn't reversible at all, how would I adjust? I have absolutely no idea - if I knew what the experience would be like, I wouldn't be interested in having it. If it was involuntary, I'd probably go for vicious revenge, not out of anger, just out of principle.
EDIT: Huh, interesting, at this point, only 27.8% of people have responded negatively to this idea. Maybe the OP is on to something.