That’s dealing with two different considerations at the same time, I suggest breaking that down:
1. Hosting
Decide if you want experienced professionals to host your Discourse securely without having to be responsible for as much maintenance. If you have significant technical skill that may not be necessary, but you may choose to do so to cut down on the time you need to invest.
2. Technical Architecture
If you do want to host it yourself, you can choose to host it on a separate VPS (nice and simple, official install), or use the same server (non-standard multi-site install, more complex).