All of the bootcamps I know of focus solely on web dev. That's not necessarily a bad thing. Plenty of places need web people, and you can always keep learning and transition to something else if you want.
Here's the advice I usually have for people that ask me if they should do one:
* what did you do in college? I found that people who did some sort of STEM major caught on much more quickly than those who did something like Art. Basically, if you've had a lot of experience with problem solving and critical thinking things should come easier to you
* go in with a project in mind. Learning with a purpose and intent (I want to build X, what do I need to learn to do that?) is much more effective
* don't believe the job placement numbers. Prepare to be on the hunt for 6 months after you finish
* try to talk to people who did the specific program you're interested in. This is a big one. LinkedIn is your friend.
* if you do go, don't mention it on your resume. Plenty of people just throw bootcamp resumes out. Just say you're self taught.
* you won't learn to code just by simply showing up to class. It takes a lot of effort outside the classroom
That's all I can think of for now. I had a tough time finding my first job, but if I had to do it all over again I'd do it in a heartbeat. Feel free to shoot me an email if you have any questions.