Hi Robin,
I’d say android then.
You can have a look at our list of recommended android hardware.
And here, under ‘feature comparison’ you can see main differences between windows and android clients - http://xibo.org.uk/about/
Windows client is distributed under open source AGPLv3 licence, so you can try it for free.
Android client comes with built-in 14 days trial licence, so you can do some testing on your own as well.