Somebody made a post a while back, something along these lines, and I think they said something to the effect of, "I'll just enlist, then apply for MECEP, life will be grand and I won't have any worries." My reply was pretty pissed off and lengthy, but somewhere in there I said, "Applying for MECEP (or any other enlisted-officer program) is not like applying for a Discover card-You are NOT preapproved."
Anyway, what I'm getting at is that I would not trade my enlisted time for anything. But once you are actually a Marine, things get a little more competitive. The number of Marines accepted into MCP/ECP each year is less than 100. The number that get into MECEP each year is roughly 100. And there are a lot more Marines out there who want into each program.
The big issue that everyone has mentioned is our wartime situation. If you enlist now, active or reserve, I wouldn't put too much faith into going right to college. May have to wait a while.
Like jboomer said, being an enlisted Marine lets you see a whole different side of things before you cross over to "the dark side". But just be prepared for possible activiation and deployments, then year(s) of heartbreak trying to get into OCS. I applied for MECEP three times (three years-I was damn near too old the last time) before I got in. Good luck.
Staff NCO's never die. They just go to hell and torment officers.