I've upgraded from 6600 to 7700,now to 8900. I think it's a big improvement in terms of FMQing without eyelashes and the necessity for "quilting words". I like the improved lighting,smooth and quiet operation,ease of use of quilting foot,the options for needle position,the improved 1/4 inch foot. It is a real work horse.
Since I got it,I have breezed through a variety of projects,including easily quilting a queen size quilt.