I bought this to substitute an Alnico Jensen in my Victoria Pro amp (tweed Fender Pro replica).
I was never happy with the sound of the original speaker. It was missing mids and always had a harsh, unpleasant aspect in the highs. This held true regardless of the guitar, pedals and tubes used with this amp.
After dropping the Fullback in the amp sounds amazing. There's great lows, mids and the highs are somewhat tamed, while keeping some great sizzle with overdriven sounds and sparkle when needed.
Goes to show again, that if the speaker doesn't suit your taste, no changes in the rest of the signal chain will make you happy.