We used it last year - it is the greatest thing ever. Here is a breakdown:
We got if for free due to the promotion last year, but it would of cost us roughly 800.
Looking at my "tally sheet" (I kept track of how much we didn't pay due to the dining plan), we had (for 3 adults and 1 child), $1200 worth of meals put on the dining plan.
So, overall, it saved us roughly 1200.
Definitely worth it.
Even better if you can share and split meals - stretch them out!