I can only speak from my own personal experience which is limited to a single 6 week "experience" during 3rd year but....
I would NEVER choose ob/gyn, and here are my reasons:
1. The prevailing attitude that only women should be ob/gyns because women should care for women. This is ridiculous, but the bias is real and it will affect you if you're a man in this field. The chiefs that are graduating from my university have had different experiences. The women all fielded multiple offers in desirable places. The one guy chief received no offers in the city that he really wanted (not even that cool of a city), and took a job in rural New York. On my rotation he was bitching now and then about how the job search was sucking for him compared to the women. Women get better financial packages too. Not in every case, but this is happening a lot now.
2. The fact that as a male, you will have to have a female third party present every time you do an exam. What are the men gonna do? Rape a patient? There is an implicit accusation here that men are somehow more likely to be unprofessional than women. Or at least, more likely to be accused of being unprofessional. Either way, that sucks.
3. Too much estrogen. I don't want to be the "token" male. God, it was bad enough being a med student on the service watching all the crazy female dynamics... Pretty much none of the residents ever seemed truly happy. They always looked like someone crapped in their ice cream. Hard residency? Sure. But no one put a gun to their heads to make them do it.
4. Cervical exams, pap smears, etc... I just can't imagine doing this for my career. There is some pretty bad hygeine out there...
5. Poor surgical technique. It's really bad folks. Really variable surgical quality ranging from good to horrendous. A 4 year ob/gyn residency is just not sufficient to train someone to be a surgeon imho. Besides, a significant portion of your time is spent doing PC stuff. Gyn onc was pretty impressive, but then you have to do another 3-4 years of surgical training for that anyway.
6. Horrendous hours. I'm going in to gen surg, so for me to say this probably means something. With the 80 hour rule things might calm down though. However, I found my ob/gyn rotation to be more grueling than most of my surgical rotations. It's not that I was doing any surgery, it's just that I would stay up all freakin' night delivering babies. Big whoop. After 10 or so deliveries, you can pretty much do it by yourself. The best part was doing episiotomies, and then sewing them back up. Whoopee. Not worth staying up for imho. One of the attendings whom I really like is in her 40s and still takes in house call. Um... no thanks.
7. Malpractice. Actually I think that it would be a mistake to not choose ob/gyn based on the malpractice woes. However, it's just another strike against it. The top civil awards for the last few years have been against ob/gyns. It's just ridiculous. You will be liable for things that really are out of your hands, standard of care be damned. And with the skyrocketing premiums, a significant portion of ob/gyns are dropping the "ob" and just doing gyn. Delivering babies was one of the cooler things about this field, and not doing it cos of insurance problems? Horrible.
Finally, this is just one man's opinion. If you love ob/gyn then go for it. Just be aware that as a man, you will face a lot of hurdles that women, and other physicians in other fields (male and female) won't have to face. It's a job, and someone has to do it. God bless you if you choose ob/gyn.
Peace, and good luck.
Diane