The Twin Jet nails it for playability and versatility (as far as Ubers go), but the Rev 2 has a special tone that I haven't heard elsewhere. I have KT88s in the Rev 2 now and the player-friendly factor has gone up. Channel 1 also sounds a lot better with KT88s- more clear and chimey. Channel 2 is more aggressive and articulate, but lacks those weird mids that the EL34s give.