you guys never heard of arnold? wow. thought everyone knew of arnold. back when i 1st started my tower MR was taking 3 hours per frame to render it. then along came arnold and did it in 8 minutes. i was blown away. vray did it in under 8 minutes on a way more complex version of the tower than the one i sent to marcoss to render. i remember the days chatting with the programmer of arnold. i dont see him around much anymore. you guys can check more arnold renders here http://www.3dluvr.com/marcosss
and also www.pepeland.com
this is the arnold rendered version in 8 minutes
and this is the vray version rendered with QMC for primary and secondary bounces