They don't really compete. MLT is guided prep thru the MBA application process and a chance to meet admissions execs. They will help you structure your application process from timing when you take the GMAT to essays, visits, chats with current students, and they have a couple forums that bring together all participants nationwide. It's cool to help you connect with other minority mba students - you'll know people at a lot of schools, but I don't think it's necessary to be in nor does it guarantee you acceptance.
Jumpstart pretty much mines MLT and they help connect minority students with mostly consulting and finance companies, if you're interested in those fields, definitely get involved.
I hope you know about consortium - free ride to bschool >>>. Unless you want to work in certain parts of finances or McKinsey Bain bcg, I feel the tradeoff of attending a slightly less prestigious program for a fraction of the debt is worth it. Even then, if you're really a kickass candidate, the doors to those companies aren't closed to you.