The Keysight DSOX/MSOX series are probably still fastest when it comes to UI responsiveness. They do take a while to boot but the controls are almost instant, they have a very "analog" feel. It's a shame Keysight has been neglecting that market segment for a while now. Some aspects aren't really competitive anymore, especially the memory depth. But I'm not getting rid of mine anytime soon, I still like the way it low-key "just works" for a lot of things.
From memory, the older Agilent 54600 models had a similar feel as well.
I don't think I've used a TBS1000 but Tek has made some horribly slow DSOs over the years. I'm not judging anyone who finds that annoying.