Make sure you get the needle down feature as long as well as a way to drop the feed dogs. Another feature you want to be sure to get is the speed control, it helps having the button to keep the speed at a certain pace no matter what your foot is doing and it allows you to slow the speed way, way down which you can't do with machines that are just foot controlled.

Go to the Virtual Section for Sewing/Quilting machines...you'll find lots of good info there! :)

I have a Mega Quilter and the Brother that have larger throat spaces and only straight stitch. I love them both. I don't quilt with them anymore because I bought a longarm to quilt on. I like the button to cut the threads and they both have the needle up/down. I piece with them both because they work horses. I only use my other machines when I need to do fancy stitches.

Janome 6500

Forgot to add-
It has a larger opening.
Thread cutter
Knee lifter
came with a "quilting"table
it came with all the goodies you'd need for home quilting

I am not sure if I could live without the larger opening, knee lifter or thread cutter anymore. The tread cutter is awesome with quilting. I have used the machine extensively for both free motion quilting, walking foot quilting and binding and piecing. I sew a lot and it pretty much is all quilting!

I think the 6500, 6600 and 6700 are all similar but everytime they were upgraded a little. I think the 6600 is the first one with a build in type of walking foot. If you are looking at this machine I would probably look at the 6600 or 6700 because of the newer features but I have seen nice deals for the 6500 online.

I use the Juki TL 98QE and love it, I FMQ my quilts using this machine, throat is 9" and I can FMQ queen size quilts.

I love mine too. I used it for years on my sewing table and quilted king size quilts on it. Last year I got a Grace frame and it works great there too. I love my Juki. My kids call it Moms Baby.