The right way to create a rectangle hole with rounded corners on some surface? The right way to create a rectangle hole with rounded corners on some surface?

I have this one, but my example working pretty bad with subdiv mod.





Solution like this seems well, but without subdiv mod it haven't rounded corners. I want nice corners with and without subdiv.mod.
If you're working with subdivision, something like this is all you need:



As you can see, you can loosen or tighten the curve by bringing internal holding edges closer to, or further from, the corners, or dispensing with them altogether.