Well, I am opposite of most people looks like. I had a 6500 and upgraded to the 6600. HATED it! So sold it and bought another 6500! I am apt to go from applique one minute to quilting the next and found that having to change the feet was way too cumbersome on the 6600!
So obviously a matter of personal opinion. I know you don't like the idea but the only way to be sure you choose the right machine for you is to go try them out at the dealer.