My experience has been that it is a complement to MC. The w/e is an intense 2x4 to the relationship that helps make MC be more effective. It's also cheaper (being nonprofit, they never turn any couple away for lack of finances).
It's different than MC in a significant way: you never share any of your issues with anyone else - not the presenters, not the other attending couples. You listen to presentations given by ordinary couples, then you & your spouse talk about it alone in the privacy of your room. It sounds like it might not be that big a deal, but you'd be surprised.
