Stick to the National Park. Don't waste your money.
We visited Gand Canyon West on the way from Flagstaff to Las Vegas. It's a long way off the main road but we hoped the Skywalk experience would be worth the drive and the price ($365 for a family of 4 including a meal). Sadly, it wasn't.
The Skywalk is short, at the end of a very long queue and is covered in a dirty, scratched protective film which ruins the view down through the glass. The views around, of the canyon are, as you'd expect, spectacular. But very the worse thing is (and this is not made clear until you've got to the end of the queue) is that you can't take cameras or any personal belongings out onto the Skywalk (they must be left in a locker in the building). If you want a photograph they you have to join another queue and pay an additional $65 for an official photographer to take your photo. There's no good reason for this other than to extort more money from people. The admission price is already high enough!
The meal was fine. Tasty and plentiful.