No, no problem at all for average. The complaints come mostly from below average flyers or people who have NEVER owned one

I have seen the 120FZ on a CG Ultimate and it was outstanding !
Put the tank back at the balance point and enjoy some nice flying without the CG shift from forward tank placement ! Dubro and the hayes tanks work well . Reinforcing the tank with some nylon strapping does no harm . The only tanks I have seen let go were the Great Planes brand .
A Saito 150 would be close to the YS 120 in power ,but not overall running.