There was $500 of value to me. It was worth it to me to spend a little more for the 2.0 (1.83 when I ordered) since I fully expect to have this machine in service for 2.5-3 years at a minimum. At the end of that time, I'm going ot want every MHz I can get to keep performance reasonable. 🙂
Since I needed the extra disk space anyway, and am never one to go for less VRAM, it was a no-brainer for me.
I doubt that you'd see much difference between a 1.83 and 2.0, but more so between the 1.83 and the 2.16. Likewise, there wouldn't be a lot of difference between the 2.0 and the 2.16.