I think the problem was with the tubes, not the amp's design.
I bought a friend's MC2102 which he had for 3 years last year and he never had any issues with tubes or reliability. That is one of the reasons why I bought them, as well as the great sopund.
Since Dec 06 I have 2xMC2102's running parrallel mono blocked and no issues whatsoever.
I have replaced all the stk input and output tubes on both amps and again no problems.
Only great music.