Based on how you have describe yourself, I think you might prefer Mercersburg. There will be plenty of challenge and rigor, but it’s more nurturing. You can’t assume you’ll be a big fish in a small pond there, but your shine is more likely to be noticed there.
L’ville is definitely more well known but it’s more amped up on a number of fronts. Partly because of its size, partly history, partly history.
You really want to pick the place where you will thrive. Being at a well-known school cannot make up for it not being the right place.