Along side the fact that one amp is all tube, and high on power, there are a lot more things that a good amp should have. Manufacturers of cheap tube amps know that people often don't look about detailed specs, or reliability issues, how much they like to see labels like: "all tube design", "4 channels", "high quality FX effects", "ultra mega giga EQ boost" etc. Have you ever noticed that most of the time low quality amps do have these stickers on them?
My point is simple. Good amp is expensive and we all know why. It is a standardized model, built from good quality components, built with care, properly tested (not only by company tech, but also by musicians all over the world gigging and touring), and you just know that these amps are good and well worth of money, and you're paying for device that will serve you well in the years to come.
So to conclude save for a good quality tube amp that you will be satisfied with. Guitar amp is after the guitar the most important (and expensive) piece of gear, so it is always better to buy a quality one. Giving 700$ (which is a big amount of money) for something that you will not be pleased in a long run is a bad investment.
okay