You can certainly fmq on this machine! (You can fmq on almost any domestic sewing machine, even the ones that won't drop the feed dogs. In that case, you can cover the feed dogs.) It is a great machine. I almost bought one, but I already have a great Bernina 1230 and could not justify the additional expense. The Janome has a larger area under the arm, which makes fmq easier for large quilts, has a much larger flatbed, and it has the automatic thread cutter I covet. The only thing it doesn't have is a free arm for sewing cuffs and pant legs.
I'm pretty sure a Bernina with the stitch regulator would cost a *lot* more than the Janome 6600.
A lot of quilters on this forum have the Janome 6600 and really like it, so I think your dh did well (except for not consulting you first!).