A friend of mine has a Sony tube HDTV, and it looks very nice. That's all I can really say. I don't have a lot to compare it to beyond my own much older tube HDTV.

There are really only two HD standards you need to be concerned about: 1080i and 720p. I think it's a little up-in-the-air as to which is "better". You might want to see if there's a particular set of shows you want to watch in HD and see what most of them are broadcast in. You should be able to watch all of them, though, just converted to whatever your TV will display instead of native. I haven't noticed any wild quality drop in those conversions.

Well, there's also 480p (formerly known as "progressive mode"). It's what progressive DVD players produce, and is sometimes used in HD signals to transmit non-HD programming. You ought to make sure it supports that, too.