There is no simple answer to this question.
Oldest Academy kits are copies of Tamiya models. Later they started making their own models and initially they were not great. Their latest releases are however quite good, even very good in some cases.
Revell models in 1/35 are in majority reboxes of Dragon, Italeri, ESCI or AFV-Club kits. They also made several their own kits, but these are not very good. They can be built into nice models, but it requires a lot of work. Situation is completely different with their new 1/72 armor models that are among the best available.
Please note however, that my experience is based purely on modern armor kits. I don't know anything about WW2 models.
Rgds,
Pawel