Beto for me. While policy is not as established as some of the others, I think he's proven to be thoughtful, intelligent,kind and a clear understanding of the issues facing our society,. I trust him to always do the morally right and intelligent thing, and is the only one who can get the country on the same page.
While it's not popular with ERA, dragging the red states kicking and screaming into a progressive society and government is just not going to work without someone who can appeal to their sensibilities and won't stoke their fears.
I love Bernie, Warren, Harris, and many of the others up there, I just don't see the being able to push a progressive agenda to those states, and Beto can like he did in Texas. It's maybe not the push for change many of us would like, but I think he's the only candidate who can get widespread support in those regions.