Which are the main differences between HP Prime revision A (product code NW280AA) and revision C (code G8X92AA)?
While there may be other undetected issues, the main differences are related to the USB input-output possibilities. By looking at different websites around the web (mainly the French tiplanet.org and the American hpmuseum.org), these are:
While the second requirement is not affecting me personally, it can affect the Prime as a school working tool. This is one of the things that make the Prime preferable to an iPad for a classroom.
Again, and while my children have both a Prime, I don’t think they’ll try communicate with each other with them.
There may be other differences but we're not aware of them - yet.
However, the third limitation is a more incapacitating one. The SmartStream 410, aided by the several Fourier Probes, can really turn a child into a scientist. It can successfully substitute a tester, thermometer, barometer, mini-oscilloscope, all in a single box - and can make them think independently and design their own experiments.
I don’t think I would buy a new Prime if I had revision A; while I am sure I would do my utmost to get revision c (code G8X92AA) - more so when they are exactly the same price. The main problem here is that the sellers can’t tell one from the other reliably!
And there is nothing in the calculator body that can tell them apart!