Don't take this wrong, but I've always felt that the Vaio's were more hype than substance, I always felt that they were a bit cheap (quality wise, not price wise). My friend had a Vaio desktop, and it was literally made of plastic. Maybe there is a steel frame inside, but the outside was all plastic panelling, including the flaps leading to the drives. Those promptly broke. Now, it was the desktop, and I don't know if the laptops are better, but that experience alone kinda put me off of Sony computers.
Just that if I'm investing that much money into an item, I want it to be one of high quality.
Anyway. About the processor, I don't think that extra 0.2 Ghz is worth that extra 500 bucks...the performance gain simply isn't enough to justify the cost. You can buy another laptop for that much.