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.