I did a bootcamp course in London last year, I found it really worthwhile.
Started in August 17, finished in October 17 and was lucky enough to have two offers to choose from in early February 18. The thing you are really paying for here is the portfolio pieces, especially if you get to work with a business on a project, as this is what all the employers I interviewed with wanted to know about.
Like AnaSantos has said, finishing these courses are just a start on the learning journey.
Not sure about Amsterdam but in London the market is saturated with Juniors looking for their first role. You meet loads of people who are making career changes at meetups etc. I personally would be quite skeptical about any job guarantees a course offers. A lot of the time the companies that offer these courses will consider you doing a short 2 week freelance gig for a startup as you successfully being placed in a job. When really you should be looking for a longer term role to learn and grow as a junior.
Almost everyone in my course (18 people) was in a role as of around May/June 18. So my advice to anyone considering a career change is to be prepared for a potentially long period of job search and the frustrations and challenges that this brings. But its worthwhile once you land that job:)
Anyway, all the best mate