I've had the genuine one from Quickvet now. It's difficult unless you have both to compare, but the genuine one looks less crude, the plastic is better moulded, the steel is more finely ground and the teeth better engineered, and and it has the name and US patent nos embossed on the plastic, which the fake one didn't - it had nothing on the plastic
What alerted me to the fake one was the packaging, in which the printing was blurred and there were spelling mistakes the text of an improbable kind: shlution for solution, doweward for downward, profeddional for professional, and for any. The US patent nos and the copyright statement were not included on the fake one's packaging I looked at genuine ones in a local shop yesterday and the packaging there was similar to my proper one, although there was a bit more in other languages.
On the topic of fakes generally, I take the point about if it does the job etc., and I wouldn't give too hoots about fake "designer" clothing, but trademark and copyright protection exist for good reason and if they are marketing such a thing they should not use the name even if the original product is "overpriced". Even without using the name they would be violating the patent.