I'm staying at Vero Beach for the second time (I leave in 13 days!!). I really like it, but I really enjoy beach vacations. Like the other poster mentioned, it's definitely more of a relaxing vacation -- there are things to do on property but if lounging all day isn't for you, you'll be bored in a few days. There are things to do in the area that are available through the resort like kayaking and such. We've rented bikes and boogy boards and did some mini golfing but otherwise we just sat around. If you do go I recommend checking out some other dining options in the area. We enjoyed Captain Hiriam's (good seafood - occassional crab specials) and Mr. Manatee's (cheap oysters).
It's a really pretty resort with just a touch of Disney so it's a nice balance for me (Disney fan) and my boyfriend (not so much).
I don't have the coupon with me so I'm not sure of the days but the 2007 Birnbaum guide has a 15% off coupon (if you're not staying on points). Spending the $12 or so on the book saved us a good chunk of change.