Buddy Rich was the GOAT until Virgil Donati came along... Trust me when I tell you.. Virgil is on a entirely different planet than Rich was on... Rich was stuck in one Genre(Jazz)... Donati does it all... Jazz, Fusion,Metal,Prog Rock you name it... Donati does things with odd time signatures that Rich couldn't master. Not saying he couldn't..He only cared about Jazz and was stuck in his own bubble. when it comes to Calaiuta and Donati.. You can't keep up with them in terms of were the 1 begins.. Or it ends.. I've played Drums and Percussion my entire life besides Guitar (My main) , Bass and Piano/Keyboards.. And some Mandolin on occasion.. I was born with a metronome in my body... Had Rich dropped the attitude and explored more then yeah.. But Rich , no doubt was the greatest in his era.. Donati and Calaiuta were influenced by him.. No doubt about it.. If you want to go on pure technique.. Mike Mangini probably blows them all away... But when it comes to all around feel, tonality and technique... Donati is the KING!