The 7700 has more features and would definitely be my choice if I were using it to quilt. I have a 6600 and used to be a dealer. The 6600 and 7700 are both made for more 'tabletop' quilting. Janome has a mid-arm made specifically for a frame. It is about half the price of a 6600 and only does a straight stitch, but is made for use on a frame. It is also a little more heavy duty. Congrats!