I'm looking into possibly trading my '71 Twin Reverb /w Altec 418C's for an amp I've never had the opportunity to play, a 1978 Mesa Boogie Mark I. I don't know ANYTHING about these amps but am curious enough to entertain the thought of a trade. Can anyone shine some light on if this model of Mesa holds any type of clean against my Twin? Any higher collector value? Versatility? Are there better Mesa amps out there that I should check instead of the original Mark I?