Walkthrough tips, Campaign discussion [Heroes 5: Hammers of Fate].

Even though there are fewer neutral creatures on Recruit difficulty, each defeated unit grants more experience, so the overall experience gain is roughly the same.

That's true, but experience is still gained faster on the hero than on a regular unit. At least in campaigns. I haven't played much on other difficulty levels, so I can't compare them.

Definitely: most missions are much harder to complete with a hero than with a regular unit.