Tree style tabs is more stable and performant but also has a few nice addons (TST Colored Tabs being one of my favs). Sideberry can be infinitely customized but I found it to be extremely slow with 100+ tabs across multiple windows.
I will not defend this use model to any skeptics, but FWIW I have no performance issues!
Sidebery lets you set colors on tabs explicitly, or by pattern. I use this sparingly but it's very useful when I do.