To put this into perspective:
A new experimental build gets released at least once or twice per day. Each update changes at least one thing in the code, whether it’s spelling mistakes, removal of unnecessary code, bug fixes, and even new additions to the game (recipes, monsters, mechanics etc). The largest amount of changes I’ve seen in an experimental build was about 30 changes at once.
By playing the 0.C stable build, you’re missing out on about 9 months of constant bug fixing, balancing, monster additions, item additions, mechanic changes and more. It’s quite ridiculous how outdated the stable build really is, but I’d recommend for newer players to try it out first before jumping to the less-stable, sometimes even partially broken experimental builds.
You can follow the latest experimental build progress and view changes/additions here.