I've met a few guys who have taken them, but I'll only tell you of a former wing who I hung out with a lot and trust to give an unbiased opinion.
He took the RSD bootcamp and told me it was crap. Most of the instructors refused to approach and when he finally convinced one to approach, the girls just blew the guy off. He then came back to wing and tried to act like it was all a big joke and he didn't really try, but wing was not impressed. He told me that some of the intructors were kind of weird and had very poor results the few times they did try approaching women.
Same guy also took a MM seminar. This was quite a while ago and he told me Mystery was actually teaching some of the workshop at this time. He told me it was quite good. I should also tell you though that VA instructors use props, basically paid girls are part of the show, so with Mystery you really never know what is real versus his illusion of real.
Basically, these guys take all your $$$$ and that's what they build their supposed "lifestyle" with. You could just as easily call yourself a guru, take a bunch of cash and buy a fancy house complete with hookers and party girls and you'd be a guru too! That's not to say some of the advice isn't good, as much of it is, but paying thousands and thousands makes no sense at all, especially given the somewhat dubious nature of some of the people involved.