One thing I do love with the Janome Horizon Memory Craft range (15000, 12000, 8900, 8200) is the AcuFeed Flex feeding system that lets you quilt through multiple layers.
NB. The Janome Memory Craft 7700 and 6600p use the AcuFeed system, which is a precursor to the AcuFeed Flex system.
Which everyone knows is a must with quilting.
Well did you know that there are two versions, the wide and the narrow.
I find the narrow version is very handy when attaching bias binding as well as in general garment construction.
These feet are great to have on hand when dealing with difficult fabrics, because they feed the two layers evenly preventing the fabrics shifting in different directions.