I'm AmeriCorps alumane.
I think it really all depends in the program you choose. I had the opportunity to meet with people from all the AmeriCorps programs in my state (NJ) and some people hated their experience and others loved it so much they signed up for a second term.
I enjoyed my program, because it gave the opportunity to try different aspect of the envrionmental field before leaping into a carrer. Down side would def be the pay, because you are volunteering for a year, but you do get about $5,000 back in education to either put towards future education or pay back student loans. Plus the loans are in deferrment while you are a Corps member.
My advise would be to try and talk to former members of the program you are specifically interested in. Find out what their experiences were, and get them to admit both the positive and the negative. If you have any questions, feel free to PM me
ETA: There were 3 other sorority alumane in my program and we would always joke that our AmeriCorps logo sweatshirts were alot like letters because you couldn't wear the logo while drinking, at a bar, while participating in politics, etc. There is a whole list of prohibited activites- much like most of our bylaws.