My experience with Tabnine was that I loved it when it came out. I loved the fact that I could get full line suggestions without any extra language specific setup (I hop around different languages a lot) but the suggestions became less and less useful over time. In my view this was a degradation of Tabnine but of course I have nothing to back this up. Hearing this backstory does reaffirm my suspicion.

At some point I started using Language Server (mostly Typescript and Python) suggestions alongside Tabnine and it started to feel like it was just getting in the way. In the end I got rid of Tabnine. I haven't tried Co-Pilot yet but may give it a go when I find some time.