I think Garden Grill will be great for your 3 yr old! We tried it this past Feb for the 1st time. Our DS was 2.5 at the time. It is a very relaxing character meal. You stay at your seats & are served family style w/unlimited amounts. The characters walk around & spend lots of time w/you. We were visited by Mickey, Pluto, Chip & Dale multiple times each! Nothing was rushed. Chip & Dale were great too. Chip played peekaboo w/DS using DS's napkin. Then Dale used my viewer for my camcorder to fix his hair.
Plus, DS loved the decorate your own cupcake dessert. It gave us a chance to take our time eating b/c he was occupied. The corn bread & potatoes are yummy! Kids have their own food too.
We are not fans of the character buffet meals. They are always loud & kids everywhere. Then you have to time when to get more food w/when a character might be coming. Garden Grill was much more relaxing & I'd definitely do it again.