Likewise I have had no complaints about any of the nibs I have passed on.
I have a real Mont Blanc that writes no better than any other pen I have tried.
My handwriting is appalling anyway so a rollerball is preferable for me, why worry about splashing ink?
The only thing that does concern me is if I use the German nib as a selling point and the buyer discovers it is not a German nib.
The sort of customer I get ain't likely to ask for a refund, more like go to my funeral after he has shot me init?