Attention we use several devices
Our go to is Andriod, jelly bean platform. We are using 8.7 upto 10.3 samsumg A7 tablets. We have pushed them in kiosk mode for all merchants with remote access for maintaining debugging.
iOS will give issues for permissions, atleast it did for us.
Printers are tricky
Most of our merchants already have printers from their POS providers. A lot of them already have API integration with their POS provider which makes it easy to collaborate. Outside of that, the limitations of this platform it is very difficult to create a API for inbound To the existing thermal printer because every function and element of printing manufacturer is different. USA, no one uses windows for the POS. Atleast not the major players.