I have an older Pfaff (1540). It is a little fussier than my other machines (couple old Singers) -- I have to adjust the tension a bit more often when switching fabric types/weights. And I have not used many of the special stitches, etc. BUT. There is a BUT. Actually there are two BUTs:
1. The IDT is priceless. I can put a 90" zipper in with no pins, no glue, no basting. Or sew 100"+ of drapery hem. And it will come out perfect.
2. Partly because of the IDT, I think, it handles big seam bumps very nicely. Great machine for altering blue jeans, sewing backpacks, etc.
I haven't had to have any service on it over the 8? years or so I've had it. I haven't sewn as much on it as some folks have on theirs.