TennisDirector severs are oversized for what is required from them. This means that slow response times are usually caused by the speed of Internet connection or by a computer overload (memory or processor) that affects the browser performance.
No. As long as you have a working smartphone in your hands and a cell tower close by you can do with your phone whatever you were doing with the computer. You don't even need an Internet connection.
In 2016, the uptime was 99.93% and all downtime occurred during the night.