From my experience with quilting guilds in NC, the Pfaff seems to be the machine of choice. Easy to use, good service available, and the girls enjoy sewing anything on them.

I love the JUKI F600! Have sewn extensively on different machines and find the F600 makes THE most gorgeous straight stitch I have ever seen for a zigzag machine. It's also the most user-friendly computerized machine I've used.
I had a computerized Janome 7700 that I sold bc even though mine didn't have issues, I found it to be too delicate and I was always concerned that it'd break if I accidentally pushed the wrong button.
I have a vintage Pfaff that I love to sew on but personally, I wouldn't buy a new Pfaff today bc I have friends who have issues w their newer Pfaffs. I think the parent company, SVP, makes Singers, Vikings, and Pfaffs & imo, they're not the same quality machines they once were.