If you're using it primarily for home defense, then the cocked and locked issue doesn't seem to matter as much in my opinion.
Given the choice, I'd go with the P97. You could get two for what you give for the HK, and then your wife gets one when something goes 'bump'
As far as overengineering goes, the Ruger P series is as highly overengineered as any auto on the market. Just about all P series are built like a tank. I'm not sure about the USP, but the P97 will digest anything you put through it, including high pressure loads and even wadcutters. I like that.
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XRayMind
Remember: You owe the great freedoms you enjoy to a 'bunch of gun owners'.