The Gan 356 M was originally released in 2019 and has always been pretty popular, even despite it being very old now. It was essentialy a simpler version of the Gan 356 X which is no longer in production, the difference was that the Gan 356 M did not have adjutable magnets. In the past year, Gan have re-released this cube a few times, each with various modern features.
Gan first released a maglev version of the cube which allows it to feel a little faster. Gan have now also decided to release a UV coated version of the original puzzle without maglev. I think it is unfortunate that Gan seem unable to innovate and release a better cube, it seems many people continue buying this old Gan model because it is a cheap Gan cube, the Gan branding is still very strong and a lot of newer cubers simply think it is the best cube brand, they then tell their parents that they want a Gan cube and their parents inevitably look for the cheapest cube under the Gan brand, most are sensible enough to avoid the non-magnetic Gan cubes and then go for the Gan 356M which is not a bad cube but there are cubes now available in that price range which most cubers will prefer.