A year gone by, and I have the answer.
The ME330/550 combo has served me for 12K km. So the longevity is OK.
The BT45 have lasted me 12K, too. But after that, the BT45 front tyre was thoroughly worn out on its flanks, while the BT330 still has some 40% left.
Does that speak in favor of the ME330? I think not, because both the BT45 and the ME550 rear tyres are done after 12K. I need to change front and rear anyway.
However, while the grip of the BT45 has always been flawless, the ME330/550 gave me four panic moments within the last year, and I had to kiss the asphalt once.
I interpret the BT45 front tyre's increased wear as a sure sign of its better grip. Consequently, I will return to BT45.
[This message has been edited by ghorian (edited 21 November 2005).]