During the previous summer, I never/always ate pizza.
(I'm describing specific instances of (not) pizza-eating, so this is perfective)
During the previous summer, I would never/always eat pizza.
(I'm describing a tendency to (not) eat pizza, so this is imperfective)

Would you agree with the above?

The first one is perfective if you're describing specific instances of eating or not eating pizza, but the English doesn't necessarily mean that. I always/never eat pizza COULD mean the same thing as I would always/never eat pizza, so its perfectiveness is ambiguous outside of context. However, I would always/never eat pizza is unambiguously imperfective.

-- 
SuStel
http://trimboli.name