I am also tempted to buy the last Yamaha amplifier which incorporates their SIT transistors. They say that it sound surpasses the B-2, but who will have the two (B-3 vs. B-2 ) to make a fair comparison I don't know... The B-3 is only Japan version 100V, has one single trafo, one single pair of FETs/channel, 27000 micro/63V smoothing capacitors, 16.2 kg.
There are some members which own B-3 here on AK. Maybe they will be kind to shed some light on this topic.