I prefer VPSs too, but if you aim wider auditory you should at least try to support web hosting. With RDBMS it is easy. And with NoSQL it is almost impossible. Maybe this is just a matter of time, when NoSQL will be as much widely used as MS SQL for example, then maybe you will be able to use MongoDB in a web hosting.
But if one of the purported values of many NoSQL technologies is their benefit to scalability, and you are using this tech in your application because the app needs to scale, then does it make sense to deploy this ultra-scalable app on shared web hosting (regardless of whether they support NoSQL tech)?
