I went through a boootcamp several years ago. Before joining I had done a small amount of dev work (mostly trying to debug simple js errors) for an existing employer and researched bootcamps all over the country before deciding on one. Since then I've worked at several companies and have been in charge of hiring a couple people, both jr and sr to myself, and in the process have interviewed a number of other bootcamp grads. My general thoughts:

-Bootcamps are insanely overpriced for what you are getting. Most seem to have a decent student to instructor ratio but almost always the instructors are recent graduates and lack the technical skills in a lot of areas. They could help out on general syntax errors but lacked debugging skills that most devs outside of extreme entry level posses. In the past two years the cost has continued to rise almost exponentially and the trend of hiring former students seems to have continued.

-I'm sure this varies by bootcamp but they seem to paint too wide of a brush. In ten weeks they will touch on both front and back end and give the attendee the illusion that they are "fullstack devs". This is great because you have a nice shinny Quara clone to show off at the end but in reality most people will walk away with little understanding of either. I would rather bootcamps focused on one area (probably client side) and briefly touch on the other end. For my bootcamp I specifically said up front I was interested in the backend and was assured that they tailor the curriculum to the student. In reality it's more a one size fits all.

-Students can't problem solve for themselves. A lot of students (and I include myself in this) couldn't handle issues that could be solved with a basic google search. Some people figure this out fairly early, others carry it on into their careers, but it seems to be especially prevalent with bootcamp grads.

-Students walk away with unreal expectations. Having friends and family that have gone through bootcamps in both large and small markets the salary and employment numbers don't seem grounded in reality. I'm sure this depends on the market but it seems like a lot of people end up taking short term low paying jobs straight out of bootcamp and while some of them find other dev jobs a not insignificant amount don't. Also a lot of people end up being pressured into taking tech but not dev related jobs by their bootcamp, presumably so they can collect a placement fee. The bootcamp I went to is fairly well regarded (you have probably heard of it) and I've never been contacted by them about my employment status, and I know a fair number of people either went back to their old careers or are marginally employed in the tech field (yet they still claim a high placement rate).

-I'm SURE this depends on the bootcamp but mine seemed to openly play favorites. At first it was great because of extra attention but after a number of staff openly ridiculed a guy on the spectrum I became extremely disheartened. A bootcamp should be about education, not a popularity contest.

After my bootcamp I didn't feel ready to be employed and opted out of the opportunity to meet perspective employers. This was met by numerous "talks" by the staff trying to convince me to attend, presumably so the bootcamp would get a cut of any offer I took. In the end I spent a fair bit of time consulting in my previous industry before finally feeling ready and taking a job as a developer (although the job search in a new market was brutal). Since then things have been great and I'm extremely happy with where I ended up, but I'm still disillusioned with the bootcamp model. Part of that is at due to my experience and partially due to interacting with bootcamp devs both in interviews and with employees at my current company.

We are starting to look at hiring two new people at the company, one is for a non dev role who might have to deal with some basic html and css, I'll probably hire out of a bootcamp for this position. The other will be for a full dev position. I'm hoping to poach within the company on this one (from somebody with no experience but who has the interest) but if not I'm going to give self taught or CS grads priority.

If you are looking to change careers and just want to work in tech. A bootcamp is probably a way to get your foot in the door. If you really love programming go back to school (I wish I had, cs masters are pretty cheap) or really work on your own, network like crazy (buy as many beers or coffee for as many devs as possible) and build something really cool. Most people won't notice it on your resume but one or two out of a hundred will and that is all that matters.