MECEP or Reserve Route to commission Marine Corps?

I am currently in DEP for the Marine Corps Reserve. My plan is to go to boot then MOS school then go to college and do PLC to attempt to commission to 2nd LT and hopefully be on route to become a pilot. But recently I have been hearing a lot about MECEP. My question is should i switch to active and go the MECEP route? Which Route is better and which leads me to being a better Marine Officer. Also what is some fast ranking MOS that will get me to Sergeant quick? Can you use your GI Bill in MECEP if you served four years active? Thanks in Advance