Proper tablet / mobile support will come, at the moment is better if you look through a desktop computer.
At the moment we don't have yet published a pricing policy, we have just throw everything on the internet to learn if this is something interesting.
Just to have an idea, the total cost will be the cost of VM on the chosen public provider, plus a fee for us for the management service.
The problem on how to put custom mods isn't solved yet, but we are thinking about giving FTP access to the game data folder, or just package the mods in the base image if they are famous enough.
At the moment everything is on Azure since we got a bizspark plus offer and we are not paying anything for it.
Please, don't ask what I think about Azure.