I haven't studied Sanders positions enough to really know whether I'd prefer him over Clinton, but it's certainly possible. I don't think it really matters though since he is still a huge long shot and I'd almost rather have Clinton anyway since I think she has a better chance at winning the general election. Relative to politicians in general I don't mind her at all.
As far as the Republicans go I've seen enough to know that I don't want a Republican. And I really don't want Trump or Cruz. Rubio is the most likely Republican candidate and is very conservative, yet he also has a better chance of winning against Clinton than Trump or Cruz, so really he's the most "dangerous". There are others still with a chance but none that have broken into the top group yet.
My vote won't really count in the primary or general election, though, so really it's just me watching it all happen.