The question insists on a practical, not a technical answer.
Phase detection is better at focusing on moving subjects, or subjects where contrast is not available because of low-light, for example, when shooting sports. Contrast-detection can be faster than phase detection where subjects are not moving or where contrast is plentiful, for example, in a studio lit for a portrait. This becomes a practical issue nowadays because the phase detection cameras and lenses are much larger.
Only the larger DSLR (Digital Single-lens Reflex) cameras with a pentaprism and mirror or DSLTs (T is for the translucent mirror) cameras have phase detection. One might object that the smaller SONY NEX5R and NEX6 are really tiny DSLTs and have phase detection, but there are so few lenses that can take advantage of this nascent technology, that one can still safely generalize that size matters. Awkward threatening huge lenses of DSLRS will continue to dominate the sidelines even if the form-fitting less-threatening tiny lenses of mirrorless cameras are favored by the old range-finder street-shooters, world travelers and outdoorsy types, clubbers who have realized the limitation of their smart phones, semi-professional soccer mom and b-camera camera assistants at weddings (heck, practically everyone else.)
Most people are NOT shooting sports or wild game professionally, so in 95% of all shooting scenarios the new smaller mirrorless contrast-detection cameras are enough. For about a year now these smaller camera have even had weather-sealed camera bodies, extra battery grips for long days of shooting, competitive image stabilization, and reasonably high frame-rates per second. The micro four-thirds ecosystem even includes fast bright lenses, with beautiful bokeh, to rival their dinosaur ancestors. And because, when shooting video, DSLRS also focus with contrast-detection, these smaller cameras are often better, simply because the interface is easier to use, for example, because of touch-screen focusing or because the screen swings out so you can hold the camera wherever you want.
Would you prefer a cheaper, lighter, smaller and subtle camera that can shoot most everything, or an expensive, heavy, large and obvious one that can shoot anything that moves? This is the practical choice nowadays between these two focus systems.