Android or iOS

https://strawpoll.com/polls/1Mnwv4e7ky7
And Why
Mine : Android Cause Freedom

iOS DansGame

iOS because it's compatible with a lot of devices I've got at home (apple tv etc)

Depends, if u want to do crazy stuff, without restrictions android is the best. Be it emulation, running custom scripts or your own UI( to an extent). Much much bigger play store too ,be it random apps or indie games. Basically everything is possible. Tho its def way less security focused(some of the chinese ones are borderline illegal) and is way more unstable. I cant speak for hardware/cameras as there are lots of choices in Android, some good, some bad.
edit: The ecosystem argument can be made both ways and a lot of third party companies offer no or limited support with iOS devices