I have owned both the 6500 and the 6600. The 6600 wins the race. Yes, sometimes things snag the built-in walking foot lever, but that's usually when I'm pushing a queen size quilt through. If I ever had to replace this machine, it would be with another 6600, the Accufeed is simply amazing. I also have the Memorycraft 10001 and enjoy it well, but, I can't give the 6600 enjoy praise.