I would also personally consider just open sourcing everything (or at least core features) as I think you'd still have plenty of customers who would prefer a hosted solution. In my experience, there is surprisingly little overlap between the people who prefer cloud vs. self-hosting, so having a full open source option doesn't cannibalize the product side as much as you might think... people who prefer cloud will mostly still prefer it even if they could self-host instead, and people who prefer self-hosting will generally just look for another project rather than using your cloud service. Just my unsolicited 2 cents.