I had a Janome 1600 for a couple of years, and you had to keep the tension disc cleaned or cotton fluff would screw up the stitch tension. Other than that, it was flawless. I had a bunch of commercial feet for it which greatly expanded its capability. The feet cost about $5 a piece. Quite cheap when you compare domestic machine feet. I sold it last year as I wasn't doing anything with it. Probably should have kept it, now that I think of it. Might get another one or maybe a Juki 5500 Commercial Strait Stitch Machine.
John