This is the cup holder for the use with the Maxi-Cosi Axiss car seat as there isn't one built into this seat at all.
Whilst is does the job great, and most juice cups fit into the cup holder, my unruly son does like to lift it off the side of his car seat and then hold it out towards me (whilst I am driving) for me to hold!? This is not ideal and most of the time I have consigned the cup holder to hook over the side of the chair near his head. I know he can't then reach his juice, but a passenger can albeit a little awkwardly!
Also, even if the unruly son didn't lift the cup holder off the side of his seat every 5 seconds, whichever side you rest the cup holder on, you have to remove the cup holder and hook onto the back pocket of your drivers or passenger seat whilst you then use both hands to pull out the levers of the Axiss to make it swivel round to get the child out.
So pros and cons, once a child has the grasp of why it is important for the cup holder to rest there beside them then great, until then it's consigned to above their heads or hooked onto the back of the cars own seat in front of the child as handy storage but not an active drinking possibilty for the child!