I guess the question is: what do you want to know about tube amps? Do you want to know how they work? If you do, go to the tech talk and Lordathestrings or pstring (others too, but these guys know their stuff) will certainly be able to give you a run through of that side of things. How they sound in comparison to solid state? What are the differences between tube amps and solid state?
In my opinion, solid state amps are great for clean tone at any volume, especially with a hollowbody jazz guitar, which have lots of tone in them already. With solid body, you generally want the colouring that tube amps give the sound, and if you want distortion, tube amps are much better at being "overdriven" so that you get a smooth distorted sound. Tube amps are more expensive, and in the long run are harder to maintain. If you are a beginner, you'll probably get a lot of use out of a decent, nicely priced, much lighter, solid state amp. If, on the other hand, you already have a solid state amp, or you have been playing a while and are interested in particular tones then look into tube amps. Even though you can can get cheaper tube amps that are as good as these, you've got three main categories (this is fairly loose). Fender's are weel known for great clean sounds for amps like the Twin Reverb, and nice bluesy overdrive, generally what people talk about when discussing "American" rock sounds. Marshall are famous for their "British" distortion, and are amps you often hear in higher gain, old style heavy bands, ranging through punk and older rock played with more gain than blues (Hendrix played Marshalls). Mesa-Boogies, though making many types of amps for jazz and rock, created what is practically THE defining sound of "nu-metal" with their dual and triple rectifiers. These three types of amps are a good overview of the sounds you can get from tubes, though other brands are, from what I've seen, every bit as good, such as Laney, Ampeg, some Carvin, etc. Go to a store and try 'em out, and have fun!
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