In my business I see a few of the different 441 style machines. On this forum the good thing is that suppliers base their business on the work they do to to set the machines up for their customers and their after sales service I have seen threads in other places that claim that certain suppliers have "better" parts than others.
Over the last few years I have played with all of the various GA441 machines from China and while some people may claim that they have special parts in their machines all of them come with exactly the same parts list. Yes, the part numbers are identical.
Cobra decided that the Chinese made bobbin winder gives them too many issues so they deleted it and provide an external type - probably a good move - but the machine is essentially the same.
I am sick of some of the crap I see being dumped on various suppliers when the machines are essentially the same.
Buying a sewing machine comes down to location and having trust in the seller.