For a simple table of 30k items with search, sorting and filtering, vue2 was significantly more responsive during the filtering step. Typing in the textbox was smooth whereas in vue3, it was quite janky. Very unexpected, I'll need to dig deeper at some point. The code was almost identical as I compared the two in the same project.
Even the page render was faster with vue2 which was also surprising. I think it might have to do with the way that every array object now needs to get proxied. It could be vue3 is more powerful but at a cost though I imagine it will go down over time.
It's also likely that I'm simply doing something wrong. For now vue2 works, so I'll continue using that.