I can’t really say for sure, but I think it would be interesting to try a Dropbox-based solution. I think my main gripe is that you’d be dependant on their service - if it goes down, or if they change their rules, you’d be left without any control over your own files. Hosting yourself or hiring a professional host would be preferable, even in an ideal world.
Is it alright with you if I try and implement your folder-per-version in my next update? I think it would work a lot better than the current method ^.=.^ If I do, I’ll try to keep the client backwards-compatible with the older system.