If you've played both, are they similar? My kids loved the Toy Story 3 sandbox mode.
I never played Toy Story 3 but my 5 years old son and I love it. We got everything out and we played it all day today.
Xbox One Day One
So excited MS bought the Gears of War franchise and gave it back to Rod.
I looked up Toy Story 3 Toy box on youtube and they seem simililar. Disney Infinity does not have any quests during toxbox mode, they are found outside the toybox, infinity I am sure has more toys and you make your world what you want it to be. Also you can unlock and download other toyboxes to play in. Similiar in some aspects but not the same