I use Copilot for its multi-line code generation. It's vastly superior. (Sorry Tabnine). Gotta give credit to Tabnine for kicking off this space -- they had a multi-year headstart on Copilot and it was pretty cool when it first launched, but it just doesn't come close to Copilot. OpenAI is kicking butt here.
Having said that, I still find value out of Tabnine -- I keep it installed it powers the pop-up autocomplete (eg Intellisense replacement). The Tabnine suggestions are immediate (as opposed to Copilot which takes a few seconds), and in a lot of cases it's super helpful for completing a variable name after 1 character, etc.
If I ESC out of the Tabnine suggestion, then Copilot takes over and a few seconds later I get a full line/multi-line suggestion.
I dunno - it's been working really well for me. Peaceful coexistence :)