Pretty much what Halls said. The only place where MMOs and PBBGs are a problem are with shared hosting (which, as Halls said, is a bad idea anyway). That is because shared hosts' entire business depends on being able to squeeze as many people on a server as they can and all of those people will be using minimal resources. Games use more resources than your average brochureware site so they are a problem. For a VPS or dedicated server, you are paying for a set amount of computing resources. Therefore if your game overruns those resources you are only hurting yourself, not anyone else sharing a server with you. Therefore at those levels you can really do whatever you want (within the law of course) with the resources you have bought.
That said, very interested to see more about your game. Just compare prices, how quickly the hosting can scale (you don't wan to lose an opportunity for rapid expansion because your host takes 3 days to expand your resources), the features available and up-time promises.
The indelible lord of tl;dr