My story is the same as Mountainmammo.I bought my Singer 401A in 1959 and the only problem I had was it wouldn't sew knits until I had a new take-up hook installed. I still have that machine because a repairman told me to hang onto it because it was the last Singer with all metal parts. About 15 years ago I bought the Pfaff 7550 which I dearly loved but bought the Janome 6500 six years ago because I wanted the larger space for quilting. I've put a lot of miles on it and it really is having some issues now. Several years ago one of the spool holders started leaning and then fell off. This is a very expensive repair so chose not to. The thread cutter is very finicky. This machine requires very frequent cleaning. Now the bobbin winder has quit. Sometimes the straight stitch setting comes up with a funky 2 stitch and then a hesitation pattern. Resetting clears the problem. I'm going to keep using it until it quits but not invest in repairs.
I had the very first Jem as a class machine but stopped using it because it had only 3 stitch lengths, none of which was good for piecing. Because of increasing heart problems I needed a light weight machine for classes so I bought the Janone Platinum 760. I wish I had shopped longer because it doesn't have the variable needle position or thread cutter.