I don't know if they are all made by same co or not. Have heard that Viking bought Pfaff.
I have a PfAFF COVER LOCK serger and I hardly use it, have only made three things with it in the past year I have had it. WOULD I buy it now knowing what I know now? nope. but my sister of my heart wore out 4 sergers she used them so much. So you have to ask how much will you use it and will it be worth the cost to you. No one else can answer that for you. hope this helps