If I had a dime for every time this question was asked, I'd have a lot of dimes...
Learjetter is right though. It's a pretty split group. I enlisted my sophomore year, and it all worked out for me as far as getting great insight, advice, etc. My buddy got hired off the street, but he had a few thousand hours flying regionally.
So it all comes down to you personally, because it can go a million ways.