High-speed trains have always been a fascinating concept. While they have achieved high popularity in other corners of the world (primarily Japan), they have been mostly absent from American travel. We continue to rely on trains, automobiles, and other forms of public transport, which, while quite fast, are not always the most efficient. Planes in particular use a lot of fuel, and are very costly to travel on (which is, in part, just due to the monopolistic tendencies of airlines). The hyperloop, however, would be America's first step into land-based intercontinental travel.
As most people can imagine, it relies on magnetism and vacuum tubes - nothing new to thoughtful people. However, on interesting thing about the design is it's reliance on only a partial vacuum (not clearing out as much air as they could), and instead compressing the air the shuttle encounters and pushing it underneath, providing an air cushion for the device. Other than that, it would still use induction principles to accelerate the train, but I find the partial vacuum interesting. Whether it stems from the difficulty of maintaining a higher vacuum, or simply trying to use what remaining air is left after what they can (feasibly) do to make it more efficient, I don't know, but there are trade offs for each.
Outside the simply physical realm, there are issues to deal with. One is cost - you're building a giant vacuum tube thousands of miles long. Another would be safety against hijack. While a plane, when hijacked, provides a much greater threat to bystanders, the presence of a giant, above ground tube is easy to sabotage. While it would be hard to cause casualties this way (a broken pipeline would most likely just have the trains slow to a stop), and if casualties were incurred they would be much smaller than those suffered on 9/11, limited to passengers, it still poses a threat, and there is no realistic way of keeping a vigilant eye over thousands of miles of tubing. So there are still a few logical kinks to work out. Not to mention that, with the forces of supply and demand in play, fares for this "tube" could potentially be inflated to near the price of airplanes, if not higher.
Regardless, I think it is a cool technology, one that I hope is applied in at least some scale. Hopefully the day when we can ride the hyperloop isn't too far away.