It sounds like you have both dealers close by, so I would recommend you take a large practice quilt piece and try it on both machines in order to make a decision. I do not have either machines, but I have the Janome MC 6600P and the Viking Topaz 20. I do a lot of embroidery so leave the Viking as an embroidery machine all the time, and have not yet tried it for quilting, but plan to with my next quilt. But when I bought my Viking the dealer really pushed how it was built to sew multi layers of fabric, and demoed more than once how may layers of denim it sewed and the beautiful stitches. I would expect both machines will do well, but it would be worth seeing it for yourself.