We stopped here during a visit to the Quad Cities area (actually the drive gave my son 20 minutes or so to nap). We saw this on a Travel Channel show and thought it would be fun to visit since we were close by, and it was worth it.
They had two semi's on display that you can get into and climb around (my toddler loves that). Other than that, its just a really big truck stop. They have a food court, coffee shop, large resturant, lots of shopping, and the famed dentist.
If passing by on I-80 I would definitely stop by! Afterall, its free :)