Okay, let's do some comparison on similar and current transportation. Remember, this is for distances less than 1000 miles.
The most common from LA to SF for fast transportation is Air. It has the advantage of having an average speed of between 250 to 350 mph. One would think it would be closer to 600 but during the climbout and the decent it slows down considerable and probably only attains a top speed of 500 miles per hour at it's best altitude. They could actually go faster but speed costs. And since the 1960, air travel has gotten slower. Not a problem as the others are either way down the road or still much slower.. Then there is the fact that you will still end up on the outskirts of your destination and will have to utilize alternate transportation in order to get close to your destination. As it stands now, in the US, it's the fastest and the best high speed short line transportation system. And the initial development costs have already been paid.
High Speed Rail. The Cost is a bit much but it's doable. But it's going to be half the speed of the Air Travel. And it takes a lot more infrastructure to accomplish so the initial cost is higher. Plus, the initial development costs are still being paid. There will be places where it's going to have to be covered due to weather and terrain. And, like the Air Travel, on some days, the environment will not allow it to operate at all. But once all this is paid for, it becomes a viable alternative to air travel at a fraction of the cost and it's much cleaner to the environment. The top speed will be slower at right around just over 200 mph so it won't be a time saver except that the time at the station should make up the difference. It will also need to feed into a hub outside the center of the city like the Air Travel.
MagLev. There is currently one MagLev Operating in the World and that is in Japan. It's very impressive. Top speed is nearly 400 miles per hour. From LA to SF it would be faster than Air. Outside of the Speed, it has the same limitations as the High Speed Rail. But it's also the most expensive.
Hyperloop. Here is an odd bird. In the 1920s, it was presented by the Grand Father of Rockets, Robert Goddard but of course, it was well ahead of technology. The only two ideas older in conception than this one is the Air and the Rail. And the Air just barely beats it out. Top speed should be fantastic. Right now, through an MIT contest, they have one winner at just over 200 mph. Not bad for a program that is about 2 years old. The speed it could reach is almost unlimited. The problem there is, the people inside. In the test versions, nausea was a problem. You are locked in a steel tube with no way of looking out being jostled from side to side, front and back. The faster it goes the worse it gets. Then there is the cost. It's the most costly to build which includes all the costs of the other alternative methods plus it's the least developed method of them all. Because of the people problem, I see it, maybe, as being used for high speed cargo but do we need to move cargo that quickly?
The one that I would choose is MagLev over the others. It's the only one that can compete with Air Travel In fact, over a much longer distance, it could even compete against Air Passenger Travel from LA to NY being that the Average Air Speed for the Air Passenger direct flight will still be just over 500 miles an hour. And there is no reason that the MagLev could not obtain those speeds. And do it more environmentally smart and cheaper.