I had them fight it out and you'll see who really wears the pants in the arena.
Hermosa is a better choice anyways as "Upgrading your Skill Training Area to
the max level with Kenneth requires you to give up a book that gives you five
skill points - the single biggest skill boost in the game. Hermosa only asks
you to give up a sword - a good sword, for sure, but it's hardly five skill
points."
Above quote was taken from a walkthrough by Seorin.Upgrading your areas 2 times is not really worth it anyways as the game does not last long enough for you to really use the upgrades to their full potential unless you reskill and put most of your points into one or 2 skills.
Wish you'd get new skills on upgrading your areas, not just allow you to take your existing skills higher as that really is not needed and worthless IMO. I did not go any higher with any of my skills then 5 and finished the game easily.