A good amplifier should be able to accurately reproduce both a Steinway grand and a Les Paul driving a Marshall stack. The magazines tend to use acoustic instruments recorded with "purist" techniques because with these recordings more is known about the sound. A well schooled reviewer should know what any number of major orchestras sound like in a variety of halls. They can use this knowledge to compare the truthfulness of a component's reproduction of music. A typical electric guitar recording has so many variables that it's virtually impossible, unless you were in the studio during the recording session, to use it as a reference for accurate music reproduction.
Based upon your stated musical tastes, you should shade your system toward components that excel at rhythm and timing. Your amp/speakers should be able to produce tones down to 40Hz with authority. Tonal accuracy, low distortion and clarity are also required. It really doesn't make any difference whether the components that provide these qualities are tube designs, or not. Enjoy your music.
Based upon your stated musical tastes, you should shade your system toward components that excel at rhythm and timing. Your amp/speakers should be able to produce tones down to 40Hz with authority. Tonal accuracy, low distortion and clarity are also required. It really doesn't make any difference whether the components that provide these qualities are tube designs, or not. Enjoy your music.