Sorry to jump back in later (holiday travel), but the point of any technique is to keep filling the tool box. Speed picking has led to a lot of rather poor and unlistenable heavy metal albums in my opinion, but it has its place. The guitarists who really blew me away with pick speed are Frank Gambale and Al Di Meola. These guys don't play a zillion miles an hour all the time. However, their ability to fill a space in a composition with a BIG cascade of notes is something most of us could only wish for.
My other favorite for big notes is Eric Johnson. His instructional video talks at length about right hand technique, and he uses what he calls circle picking. The right thumb and index actually draw circles with the pick and cross the string twice per circle. It enables high consistent speed that can easily be used to cross strings. I would not say that it is a technique I've mastered, but working it into my playing enables me to cross strings much more effectively.
Someone asked if it is easier to shred on guitar than bass. That is definitely the case. It's all physics. The guitar strings are closer together, the frets are closer together, and the strings require less force to play because they have less mass. I think instruments like mandolin are potentially even faster because the strings are shorter and return to rest faster, the frets are still closer, and the strings are tuned to fifths so you can cover a whole octave on only two strings without moving your hand. (Violins are fastest of all if you don't change bow strokes on each note, but that's cheating.) Mandolin players can crank out pretty long streams of sixteenth notes at tempos of at least 140-150. What makes it impressive is that in some of these stretches, few if any of the notes are repeated. If you haven't heard good mandolin playing pick up Bluegrass Mandolin Extravaganza. It is a great introduction that is pretty enjoyable, at least in small doses.
