the problem with the MC and taking forever to get fluid through is because the MC can not pump air. when this happens, you can loosen the brake line bolt at the MC, and pump till fluid squirts through, then tighten it back up and build up pressure at the lever. put a rag under there too, as brake fluid is nasty shit and will eat your paint. ive used a mityvac with minimal problems before. speed bleeders are better, but the mityvac works well. \ and +1 to not draining the lines if you are just changing fluid. if you are going to change pads and stuff too, i would resist the temptation to just pop in the new ones and go. whenever i change pads, i like to take the caliper off, take the pistons out and clean everything up nice and shiny and regrease the sliding pins. polish the pistons to remove dirt that will cause leaking or binding. it takes a little bit longer, but IMO brakes are very important, and its cheap insurance.