Since you quilt, the Janome 6600. The only difference in the 7700 is the higher price and free arm...as far as group discussions. Just depends on if you want embroidery too. I have the 6600 for home and a 3160 Janome for class. The 3160 is only 12.5 lbs. but has the auto thread cutter for piecing.
The Janome has Accufeed rather than a bulky walking foot. You can see where you are sewing....had a walking foot for decades...will not go back. Other more expensive brands now have the built in "walking" feature, but for the money and less service history, I would go witht he Janome. I also just bought a slightly used 350E....is has a 5.5 x 7/9" field and USB port for plug in designs you can get from the internet. It is a dream, it stops and tells you to change threads, auto cuts, & much more. It too, is not expensive....PM me if you have any other questions on the 6600 for quilting. I belong to a Janome group where you can find all kinds of information and connection to getting 15% off of all Janome accessories for your machine.
D inTX