Is there any way to trial the self hosted version? I'm rather interested, partially as someone who doesn't like the idea of putting such data "in the cloud." (For products with less sensitive data I would try the monthly subscription first.) I'm assuming not, and that the self hosted is probably a small percentage of your customer base. But worth asking!
Easiest way to get a feel for the self-hosted version is just to play around with the sandbox in the web app and enter fake data if you like. The planning experience is essentially the same.
If you did end up jumping for the self-hosted version though and hated it for whatever reason, I could always refund you.