I bought my QE4 mid-November. Couldn't FMQ with it - bobbin breaking, skipping stitches. I returned it to the store at the beginning of January. TWO MONTHS later I was told it was fixed and I could collect it. I asked the store owner to test it before I took it home. The noise coming from it wasn't because it was 'cold' as suggested........ Two days later Pfaff replaced it with a new machine.
i haven't fallen in love with the Pfaff the way I did with my Janome - and still love, lol!