In my honest opinion, looking at both sides as objectively as I can, I think Trump wins in a landslide unless we hit an economic turn, or something really dirty comes out on Trump. There has not been a candidate yet who has suggested a good economic strategy against Trump's Stalwart of an Economy. The exact worst thing you can do is say, I am opposed to 4% Growth, third time monthly GDP Growth > Unemployment in the last 100 years, significant wage growth in Women, Blacks, and Latinos.
The other weakness of all the Dem candidates is that they are running on either doing insanely dumb stuff such as Court Packing, Abolishing the Electoral College, Circumcision, and overhauling the economy with things like The New Green Deal. Most of them are being absolutely weird or saying weird stuff also. My favorite is Hickenlooper taking his mom to a porno. The Dems need a redressing fast or a unicorn candidate that will somehow capture the centrists to even have a chance. Especially with Trump having a Bigger Bully Pulpit since the no collusion.