Just a personal opinion, so take it for whatever you think it's worth. But IMO, Sanders is more of a campaign disruptor than a serious contender for the next presidential election.
He's known as a political "Independent" but as others have already noted, he's more of a Socialist really. I see some value in him wanting to bring up the H1-B VISA issue, but primarily so it encourages the other candidates to debate it.
I also hear quite a few comments from those supposedly disillusioned with "free market capitalism", so some of these people will surely find Sanders an interesting alternative. I find that quite unfortunate though. Personally, I'm still pretty firmly convinced that free market concepts really never got a fair shake in the U.S. in the first place. So often, we're sold that label while reality is quite different. Heck, I was just debating the whole issue with a friend of mine last week about the deregulation of the power companies and the disaster that created for California. He used it as a prime example of why free markets aren't really viable or desirable. I countered that actually, that was FAR more an example of fraud than anything else -- a problem that transcends politics or the type of marketplace you're working with. In fact, much of the scamming going on with all of that was only made possible because GOVERNMENT was still expected to make payments towards keeping the infrastructure working! (They had legislation in place where government would start paying out money whenever the utilization of the power lines went above a certain percentage of their maximum capabilities. Therefore, crooked businesses like Enron would create false entries, reserving utilization that was never really happening to fake capacity limits being hit and profit from the govt. funding that was theoretically going to upgrading that infrastructure.)
Time and time again, this is what I really see happening.... People get frustrated or disgusted at something that supposedly happens because of a lack of governmental controls. But a closer look makes you realize it was only due to government interference or control in the FIRST place that the scenario was set up. The net neutrality debates would probably be another example of this. Sure, we need government to step in and tell Comcast, "No! You can't merge with Time Warner!" now. BUT that scenario was QUITE unlikely to have ever happened in the first place if broadband internet service was handled in the private sector in the first place, minus govt. regulated monopolies getting preferential treatment when the services were first getting built out.