Is the QSC worth the extra $$$ ? Both are light weight, the QSC is 5 lbs lighter, but the Carvin fits in a shallower rack so weight/portability is a wash between the two. Warranty work-as where the unit needs to be serviced-is a non-issue for me so thats a wash as well. Spec's are approximatley the same - wash. The QSC has low cut filters @ 30 hz? - this amp would be used with four string basses, and I'm not usre if this matters. I guess this only leaves the sound between the two. Is there anything I'm missing? Is the QSC worth $150.00 more?