Yeah, even though I use TST on Firefox, the native vertical tab feature on Edge feels snappier and lighter to use probably because it's a native feature. Even if it lacks tree style tabs, Edge did a nice job with its vertical tabs and tab groups.
Why Sideberry over TST?
I'm using Sideberry (moved from TST) on FF and i think it's good but Edge has great native vertical tabs implementation which doesn't require any "advanced" configuration to make it work.