I'm exclusively stand-by, although I do this for speed. My recommendation, as an IT guy, when traveling is Hibernation to anyone asking.

Stand-by can be problematic when you're not just running down the hall for a meeting for two reasons:

1) I have seen laptops pop out of standby on their own following being jostled in just the right way. Now it's fully powered on.

2) Laptops can be configured to go from stand-by to hibernate automatically after a specified period of time. If something goes wrong with the hibernate process, the laptop will stay powered on and running.

The problem with each of these situations is that a traveler might not notice the occurrence. A powered-on laptop in a case, if left alone for too long, can easily overheat. The little fans and heatsinks aren't designed to contend with those kinds of temperatures, and you run the risk of causing permanent damage to one of the hardware components.