I don't have the 6600, I have the 6500. Except for the foot feed, the functionality is nearly the same. Get the 6600! Don't worry about all the extra things it can do -- it has a wonderful stitch for piecing and the larger harp to fit when you machine quilt and applique. It is easy to use, you just turn it on and begin to sew! But you can make it complex with the extras it has, if you want to. I've had it for over four years, and wouldn't trade it for the fanciest anything else :shock: I also have a smaller Janome that I use for classes, and it's a wonderful machine. But I am truly in love with my 6500
But please do find a shop that will show you, sew on it, and be sure they have good friendly customer service.
Hope this helps!
Brita