Call me old fashioned here...............but "Better Dead Than Red" Mr. Sanders (all I am willing to say on the matter)
I don't necessarily disagree with Sanders on certain issues, and I don't think he's "red". For example, I think it's absurd that the richest country in the world doesn't have a comprehensive public healthcare system. We have a patchwork of policies and agencies that sort of form a national healthcare system. Seems silly.
But he is very much like modern European democratic socialists, which is fine as long as you're realistic about the costs and limitations.
The countries which have successfully adopted this model tend to be very small (5-20 million) and have very high taxes. I don't know if people like Sanders have ever really considered the implications of trying to establish such a system in a diverse nation of 350 million. To my knowledge, it has never happened.
Another point that I think American socialists don't realize is this:
The European welfare state system did not create the high standard of living that many enjoy, so much as it preserved what was already in place.
For example, Sweden already had a very high standard of living and a highly educated, mostly middle class, populace by the time the welfare state really kicked in (1960s and 70s). That's not the case in America. We have poverty and socio-economic disparity totally unlike anything Scandinavia can imagine. People like Sanders are expecting an American welfare state to fix that, but I'm not sure how realistic it is.