It probably depends on your school, but here are my answers based on my experience:
Was it worth it- yes. It's a good learning experience if you're interested in any kind of administrative position in the future. Med students as a group are pretty whiney and being part of your school government is a good way to learn how to sort out what's important to act on and what's not. It's also a great way to get closer to faculty members that you might not ever have a personal relationship with otherwise, and you get to be 'in the know' about a lot of cool things throughout the year. Plus, it's just fun to feel helpful and useful for your classmates!
A major time commitment- kind of. It's what you make it. If you want to be highly involved and proactively take things on, it will take up more time. If you decide to be pretty hands-off then your only time commitment is whatever meetings your school wants you to attend. No matter what, though, you will end up fielding a lot of weird questions and pseudo-emergencies that always seem to end up happening right around exam time 🙂
Could you get stuff done- yes, but again it depends on your school and how willing you are to put in extra time to work on things.
Long story short, I agree with Suit. Do it for the leadership opportunity and the relationships you'll form, but don't do it just for the resume because it's a lot of work for not a lot of weight on your CV.