Skroutz.eu

I don't know which machines they fit, but in relation to the AEG one, which from what I understand is a common type of machine, they don't work, they don't create enough friction to allow vacuum formation.
For me, it's a waste of money.

The main problem with it, I had it even in the more expensive version of the ergo mx, is that the left button sticks. I assume the right one does too, but that will take longer to show, due to less frequent use.
In the one I got now, the problem started right away.
From me, it's a no, I'm looking for another trackball

Advertised as non-stick, it is actually extremely sticky. I have never seen a cooking utensil where food sticks so 'eagerly' - and doesn't come off, no matter what. Money wasted.

It is presented as non-stick. It should say "stick by excellence". I have never seen a cooking utensil in which food sticks so easily - and in a way that - if you don't want to use a metal wire, which would be complete destruction, it doesn't come off.
Absolutely wasted money.