As much as I used to love Sublime, the version switching caught me out which burned me a bit, even if admittedly my v2 key lasted an unreasonable time through the version 3 beta, but I don't want to risk buying a v4 key without a clear roadmap of when they might switch to version 5.

I can definitely vouch for this! I've been using it for many years and it's been essentially the same the whole time: fast, lean and working on all operating systems.

Combined with LSP I find it to be quite a good IDE too. Handles extremely large source trees quite well.