And the most significant decision factors are no. of users from the particular geography.
So, for e.g. if your application is used by majority of Britishers, you would prefer to host your server in UK.
But before deciding this, one really needs to test out the connection speed with the server and the related network diagnostics.
Apart from the creative and sexy UI, speedtest provides very exhaustive network diagnostic details like connection speed, latency testing, server jitter, client location and distance to server calculations etc.
A must try if your applications have global users.