I don’t work in either of these fields, but I am a repeat physical and occupational therapy patient and I can relay some of what I’ve heard from my therapists. The only thing I know about OB/GYN is that they are MDs (10+ yrs school). Your question has been open so long that I wanted to give you some info so you could move on.
I’ve been a patient of three separate groups of PT/OT therapists and they’ve told me that they all love their work primarily because they work with their patients once a week for weeks or months at a time so they get to know them a little, work with them hands on usually to help them recover from an injury or a surgery, and usually watch them heal up and walk out. This is true especially for sports related injuries because the patients are younger. The ones I’ve seen work in private practice with eight or 10 others, although my current group works out of an outpatient therapy center at a hospital. The ones I’ve seen all go home at 5:00 p.m.
Educational requirements as I understand them are a four-year undergrad degree, then one year of therapy school for an assistant therapist (APT, AOT), a second year for therapist (PT, OT), and a third year for a PT, PhD or OT, PhD. The current group I’m with, and my nephew I just remembered, all went the three-year PhD route. They are extremely competent and have helped me tremendously. They’re also nice people, including my nephew.
Be sure to talk to some people who really work in these areas. Good luck.