Why not just take a political quiz and see which one you support more? The one that was posted around here in previous parts of this thread was actually highly comprehensive and mostly accurate.
I don't based solely on the issues, at the presidential level. At a local or state level, I absolutely do.
For me, there are two things a president must handle correctly:
1. Foreign policy
2. SCOTUS nominations
After that, so much falls onto Congress. So I value electability in the general election, and after that, the ability of a potential president to wheel and deal and get things passed. Politics is the art of the possible, we can't let the perfect be the enemy of the good. I have no time for radicals or reactionaries. I don't want revolution, I want slow, gradual change I can believe in. As I posted earlier, USA 2016 is actually a pretty good place to be, far from perfect, but much better than USA 2009, and there's every reason to believe that things can and will get better. The world is far from perfect, but it is not on fire (especially compared to the past).
Which is why I'm generally pleased with Obama. His accomplishments are many, perhaps half-measures, but real and permanent steps in the right direction.
I worry that a Sanders presidency would have little luck with the Congress we have. His ideas, while appealing to young white liberals, don't feel like plausible national policies. We have states for a reason -- Vermont (which I know and love) is very different from Nevada.
So I'm going to wait and see how it all pans out. I vote in a city-state that will go 90% for the D, and there's more democracy in Iraq than here. So my actual vote doesn't matter much. (It did when I lived in NoVA).
I will vote for either of them without hesitation. There are no GOP candidates I could support.