"Tumbleweed is designed to be based off of something, not to roll forever".
It's a rolling release of opensuse. It's been rolling for years now.
I found opensuse updates the kernel almost as soon as new ones are released. KDE updates take longer to reach the repos. Sabayon was just the opposite and took much longer to update the kernel, but KDE was updated almost immediately. At least with mostly open source, I also have Flash, Tumbleweed has worked well for me. Sabayon not so much, though if you want the newest video driver blobs and kernel it's the only option.