My stated support from the beginning was for the candidate that I believe to be most likely to win in 2020. I also state regularly that I'm putting no stock in national matchups since it's painfully obvious we cannot count on these as they reflect the popular vote more than the Electoral college vote. Below is a look at each of the battleground states, and how the most recent matchup polls in those states are looking.
The below is ordered by the number of EC votes given.
Florida - 29 electoral votes - Quinnipiac from June 2019
https://poll.qu.edu/national/release-detail?ReleaseID=2629
Biden: +9 win
Warren: +4 win
Sanders: +6 win
Pennsylvania - 20 Electoral votes - Quinnipiac from May 2019
https://poll.qu.edu/pennsylvania/release-detail?ReleaseID=2620
Biden: +11 win
Warren: +3 win
Sanders: +7 win
Ohio - 18 electoral votes - Quinnipiac from July 2019
https://poll.qu.edu/images/polling/oh/oh07252019_omwb36.pdf/
Biden: +8 win
Warren: -1 loss
Sanders: -1 loss
Michigan - 16 Electoral votes - EPIC-MRA August 2019
https://www.woodtv.com/news/elections/mi-poll-dems-top-trump-but-undecideds-could-tip-scale/
Biden: +10 win
Warren: +6 win
Sanders: +4 win
Arizona - 11 electoral votes - OH Predictive insights from August 2019
https://ohpredictive.com/press-releases/poll-trumps-job-approval-decreases/
Biden: +2 win
Warren: -1 loss
Sanders: -10 loss
Wisconsin: 10 Electoral votes - Marquette from August 2019
https://law.marquette.edu/poll/wp-content/uploads/2019/09/MLSP53Toplines.pdf
Biden: +9 win
Warren: 0 tie
Sanders: +4 win
The above are all of the most recent polls, that covered matchups between all 3 candidates and Trump at the RCP site.
Below is what the matchup results above would look like on the 270 to win map. If within the margin of error, color remains battleground, if a narrow win light blue, if a solid win (6 points or more) dark blue.
Joe Biden map
Elizabeth Warren map
Bernie Sanders map
Very pleased that when it does come down to the critical states (as of latest matchup polls) all 3 of our front running candidates have the ability to take on Cheetolini!