While I wouldn't say Unsharp Mask is the preferred method, I would say it's all you need if focus was dead on SOOC, and your pic is softened a little after resizing, color correcting, etc. Smart Sharpen (I assume we're talking PS here) is more of a "big gun" approach. It uses more complex algorithms and has more user controlled options for sharpening, like correcting for lens blur or motion blur, etc. I use Smart Sharpening when I've missed focus by a little bit, and quite often it can save the pic where Unsharp Mask can't. There are limits, of course. Then you start getting into the world of Lab sharpening, Luminosity sharpening... Understanding and using sharpening is it's own discipline within editing.