Good vps is needed. Location prefer US or EU, KVM.

[Maluvatsa]

Scalability Options. Your hosting should grow with your website’s needs. Choose a provider offering seamless upgrades to higher plans.
Well, GTHost.com vps host is very professional, and we intend to keep them for as long as we have our website up and running.
I'm running more than one website on shared server, never had any problem. Everything is running very well.