I love my 8900, for sure!
the brother has superior bobbin loading and "auto"-threading systems, when compared to janome.
i mean
really superior.
however, the 8900 QCP:
comes with the extension table
has a wider maximum stitch width
offers more optional feet for its dual-feed system
must confess, the brother Muv-it seems really strange to me.
i would have to check my manual, but i don't think the 8900 offers adjustments to the dual-feed. then again, i have never seen a need for adjustments. it's truly even feed. (there is virtually no "machine creep" using the regular feet, either.)
i didn't see a quarter inch foot available for the Muv-it; the open toe is not as open as the one available for the janome. like Lynda, i use both of those feet. couldn't "live" without them. i almost never use the regular feet. i'm also tickled pink by the freemotion foot system and the results.
ask the dealer bring an 8900 QCP into stock so you can test drive and compare the two machines before you make the final decision. if she refuses, hunt for a dealer that has one you can test.
i think you'd be thrilled with the 8900, but at that price point, i'd advise against making a commitment to buy something you have not been able to play with first.