Free, open-source, self hosting CMS vs paid, online CMS?

I think it really depends on the level of customization you see yourself needing in the near future and how much time you want to dedicate to managing your CMS.

A hosted Software-as-a-Service (SaaS) CMS will get you up and running quickly but they may have a restrictive set of plugins you can install that doesn’t meet your feature requirements; they likely won’t allow you to have access to the source code or they may not permit any code-level, API-based customizations either. There also may not be a migration path: i.e. if you want to move to your own hosted solution down the road as your business grows, you may not have access to the database or a sufficient enough “export” function to get your content out in a usable format.

On the flip-side, a host-your-own open source CMS requires diligence in maintenance: you need to make sure you’re upgrading regularly (there’s usually a regular stream of security patches being released; CMSs are a big target for hackers). Like anything else self-hosted, you need to watch your logs, clean-up any comment/forum spam, manage caching, and so on.