I pretty much think most of the pizza at Disney is pretty gross. But I don't have that much of a problem with the pizza at TSPP. Really, it's not horrid. Horrid is that mickey shaped frozen pizza I can buy at the grocery store. I'd say this is like, little cesars. The garden salad is 90% iceberg lettuce, with some tomatoes, etc. You pick your own packet of Ken's salad dressing. Pizzas are "junkyard" aka veggie, buzz and woody's (i can't remember which is which), one is pepp and one is cheese. All three come with the salad. I'd personally go for the cookie over the mickey RKT, they're ok but the cookies are better. Of course, I usually get the RKT b/c it is portable, and I'm never hungry for dessert.
It's a cute arcade for the kids and a nice, cool place in the ever-hot DHS. DF and I like to eat upstairs, but then again, we don't have kids. Your son will like it, and you'll like the break.