I agree new is always better than used. However, the "reasonable" price for replacing the set on my nighthawk is $140 for front tire plus $60 to mount it. $180 for the rear and $60 to mount it.
When I heard these prices I felt like they were asking me to bend over. I don't think those prices are reasonable.
Are you sh!ttin' me? Whatever shop that is, run far away from it and never return. I just bought (from a shop mind you, not online) a set of BT021 Z rated radials. The rear is a 190 wide, and these are top shelf tires. I paid $100 less than you got quoted with mounting them up. What are they trying to sell you? Michelin Pilot Race's?
You should be able to get decent tires for $300 mounted. Even at a shop. Online and mounting them myself I would save about $70, but I dispise mounting tires and this shop is very good to me. I like to keep him in buisness so I buy my tires through him. It's nice having a shop where I can get inspection stickers and such without even bringing in the bike, he'll let me borrow tools and he gives me great prices on all my gear. Every motorcyclist should have a shop they are "in" with.