I get why people are assuming that Bernie has the edge on the Democratic side but why are people thinking that Rubio is going to take it in the GOP race?
I don't think Rubio's a favorite there by any means, but it's one state where I could imagine Trump underperforming, and maybe even Cruz or Rubio winning. The reasons being:
1) It's a low turnout caucus, and so more likely to be dominated by "party regulars", which I guess works better for Cruz and Rubio as compared to states where Trump-mania will bring a bunch of new people to the polls.
2) Trump is stronger in the Northeast and South than he is in the Midwest and West, and all of the Super Tuesday states are in the Northeast and South except Minnesota and Alaska, so if he's going to underachieve somewhere, those two states would seem like leading possibilities.
Interestingly enough, it looks like Cruz, Rubio, and Trump are all ignoring the state, at least in terms of paid advertising. All three candidates are doing all their paid advertising in the South (except a token amount by Rubio in Vermont). But I'm assuming that the campaigns will still have caucus turnout operations running in MN, even if they're not advertising.