[mamorim01]

I think that keeping things simple is key. If the device has got extra features (navigation wheels, press this key for email, you name it) then odds are something may/will interfere by sending a wrong code up to the controller and messing things up. My two Microsoft mice work just fine, but they are really old, really simple two button parts. Same for the two Cherry keyboards, no extra features whatsoever.

It is still possible to find these for dirt cheap, just peek around eBay for sub-10 euro items such as this one.

https://www.ebay.co.uk/itm/153113972461

That one is probably not the best example, but it goes to show that simple PS/2 setups are still available for cheap. Amazon would also have quite a few examples at hand (just checked Amazon UK, slightly pricier but definitely in the same price range).

I am definitely not convinced that this type of adaptors are a good solution, specially when accounting for more elaborate or feature packed devices. The simpler the setup, the easier will be for the computer to recognize both devices and function as expected. Just my opinion, anyways.

Edit: More information on compatibility issues here and here.