These are great, I’ve been using the accetto firefox images for several years. I was surprised recently when I purchased a $5 VPS and was able to use it without performance issues. I actually like using TigerVNC more with it than NoVNC because the quality is usually better, and it just seems to work better in full screen. Though, NoVNC lets you setup a machine then easily send it to someone to continue or collaborate.
There’s also neko and some other related projects that aren’t completely the same, but slightly better for collaboration.