This was a great time saver. You just have to pick up your tickets at the Will Call and they give you a time for your tour. If you get there before 10 am, you don't have to wait as long to go up.
The Chihuly is wonderful but Viator did not tell us we needed a reservation after this for the Space Needle. The Chihuly checks you in and gives you a reservation for the Needle. They said we would have to wait almost three hours for the next available Needle reservation. I had a disabled child with us and that was not possible. Were it not for the considerate staff at Chihuly, we would have been stuck. They gave us earlier tickets but told us they couldn't guarantee we'd get in but to try. You need to tell people how this combination ticket works.
This was a great deal. I take all my visitors to the Chihuly Glass exhibit so getting a discounted ticket helps as I have now been there 4 times!! There was a technical issue and it did take the staff 20 minutes to process my ticket but I would use this site again and again...