Overall, I think it's pretty good, but I wouldn't give Biden 75 percent (even though I hope it is). Probably slightly better than 50/50 and he's the best shot to win back the trifecta of MI, PA, and WI.
I think Biden is a great fit for both the Rust Belt and Sun Belt(The only candidate in the race who is a great fit for both) which would give Trump a lot of trouble. I also think he unlike the rest has a good chance of winning FL which would pretty mean Trump would lose. For Trump to win against Biden he would have pretty much run the table everywhere
Against Bernie I think the election comes down to whoever wins Wisconsin
Harris is a terrible fit Rust Belt and could very much cost the Dems MN and NH and there is no way a Dem can make up for those types of losses.
Warren on the other hand is a terrible fit for both the Rust Belt and Sun Belt . It pretty much would almost be the inverse of a Biden vs Trump race