I was told to do Med/Surg when first coming out of nursing school
and I did, but unfortunately hospitals aren't the way they used to be. I became a nurse because I wanted to be able to move around to different specialties. At the time I applied for my current position in Progressive Care Unit (I wanted ICU) I had 4 years of med/surg/telemetry experience. When I sent in my application, it was automatically kicked back to me with a generic email saying I didn't have ICU experience. I applied for PCU, same thing, the only reason I got a job was through a friend of a friend. I was told by an HR employee that they would rather hire a new grad for ICU than an experienced nurse. Basically, just know that depending on the health system, you may be pigeon holed into whatever specialty you pick first. I am having problems even transferring within the system, you apply for say an ED internship and again, you get a generic email back with no reason as to why they aren't even willing to talk or meet with you, you can't talk to a person, it's extremely frustating. Keep this in mind.
Other than that, those are 2 very different specialties. I only did OB/GYN in nursing school and honestly didn't want to get so personal with the female anatomy. Med/Surg is interesting, I have seen alot of different illnesses, wounds, procedures etc. You can also get a lot of the more unsavory characters in med/surg. I'm not saying it's all glitter and unicorns in OB/GYN, but it can get rough in med/surg. Just depends on what you are looking for.