I go for Rico....
Siguro kahit hindi umalis si Bamboo sa Rivermaya noon, we have to admit that Rivermaya is a Rico Blanco dominated band.
During those days, kapag wala si Bamboo sa gig - Rico Blanco can fill in the shoes of Bamboo (kahit na medyo sumasablay ng konti tuloy pa din ang gig) . But never did Bamboo fill in the shoes of Rico Blanco kapag wala si Rico- chances are hindi na tuloy ang gig....hindi kayang gawin ni Bamboo ang ginagawa ni Rico.
Voice quality and showmanship lang ang lamang ni Bamboo.
Pero when it comes to songwriting, arranging, playing various instruments - playing the guitar while singing, playing the keyboards while singing --- Praise goes to Rico!