Neon is explicitly a bleeding edge KDE testbed (but I'll agree that their website undersells this fact)

Neon has 2 flavors, developer and user. The user one is stable.

Sorry for the late reply. Earlier this year, I tried KDE Neon User Edition. It offers updates everytime any KDE software you've installed gets an official update, meaning you're shown updates practically everyday. That isn't stable. Again, the website copy undersells this, saying it "Featuring the latest officially released KDE software on a stable base (emphasis mine)."

edited for clarity

I love neon, so it is a tie.