Originally Posted by ZippyNH

You still get to sit through the ground portions, but you MIGHT get to skip the simulator sessions.... basically it will give you more time to study for your aircraft specific ground school, making it less compressed, and less stressful.
If you are going through your first 135/121 ground school/Indoc, and aircraft specific training, it can best be described as "drinking from a fire hose" and a few half days of the MECC will be great if you arrive fully current.