What does underrated (or overrated, for that matter) actually mean?
As far as old-world build quality is concerned, I would think the plastic guns would be the most overrated, especially the more expensive ones.
As fas as utter reliability is concerned, the various 1911s and the new "golden boy" CZ models (particularly RAMI and 75) would be the most overrated.
Having said all that, if the poop ever hits the fan, ain't nothing more assuring than having a .45 USP in your hand.
They cost as much as they do for a reason.