Like most Disney restaurants, Garden Grill was better in years past. We have gone there every trip over a long time period (15 years?) so I see how the menu has evolved.
Currently, the negative for me is that they bring very little food out. We were a family of 4 (2 teen boys) and they brought out enough food for 2 people. Yes, you can order more, but it is tiresome to keep asking for refills (we got 2 full platters then 2 partial refills of things we liked).
The turkey, steak and fish were a bit dry (sitting under lamps maybe?) although the sauces provided (we asked for them on the side) did help. The salad at the beginning was very good but they gave you barely enough for each person to have a half bowl. Dessert was on the small side as well.
The characters were great and our meal was very pleasant but I do not think it is a great value. We paid $38.99 pp plus tax and tip

during Easter. My TIW card kept me from going into full shock but I did not know the price til we arrived and it was quite surprising.
I would do it once for the experience but there are better values, for sure.
ps yes, definitely order the kids' meal if that's what you like but you might want to try at least the turkey on the adult platter: it was fairly bland and you can get gravy and mash on the side.
pps veg served was swiss chard. I mean really, how many people eat swiss chard! It was ok but I would have preferred almost any other veg except kale.