I work for Change.org and we've had considerable success hiring from these bootcamps/intensives. We will continue to hire from them, though we do use a slightly different hiring procedure.
These are my opinions, and not necessarily those of the company.
Hiring junior engineers is always risky. It's a bet against several factors that are nearly impossible to be certain about in any hiring situation, but there are several up-sides to the candidates that we've seen.
1) These are motivated people. The decision to drop everything and code 12 hours, 6 days per week, doesn't happen lightly. Contrast this to some college graduates who drifted toward a CS major.
2) These are not first-job people. Most are switching careers, but have already ironed out some important pieces of their adult life. You are less likely to encounter over-partying, failures to set an alarm, or other maturity problems that impact work or work/life balance. The end result is a more reliable worker.
3) They have a secondary competency related to their former life. Sometimes you can leverage this in their work. It's handy to have an ex-legal clerk doing TOS compliance or a sales guy helping on the ad system.
4) This tends to be a more diverse pool. The factors that still screw with women and other under-represented groups entering CS and related majors aren't as present here. If you've got a Silicon Valley "White Boys Club" monoculture holding you back, train them to fairly evaluate people not exactly like themselves and give it a try.
There can be downsides, of course. Of note:
1) These are not computer scientists. They know one or two toolkits and little or no theory. This can be mitigated by the maturity and motivation mentioned above.
2) It's up to you to effectively mentor junior employees. If you don't have a few people on staff that have the humility and patience to answer questions of junior folks, you're doubly hosed because of the lack of knowledge depth. But that's your fault, not theirs.
3) If you don't have some overlap between the toolkit they just learned and the work you're going to give them, there will be some major frustration. Don't hire a person out of a Rails bootcamp to write Java.
In the end I think this is a pretty decent, if imperfect, way to add quality junior employees.
Obligatory: http://www.change.org/careers