I can only tell you what my electrician said--he much prefers a semi-flush fixture as the heat of the bulbs (incandescent) is away from the wiring. We live in an old house and did have a flush mount fixture that actually fried the wiring. It is easy to put a bulb with higher than recommended wattage and it is definitely a fire hazard. I am changing any flush mounted lighting to semi-flush.

As an aside, I have several Minka-Lavery fixtures and they are very good quality (good looking, too!)

On a flushmount fixture, the whole "rim" is touching the ceiling. There is no way for heat to escape, and you don't get any light shining straight up from the light bulb and then reflecting off of the ceiling and into the room. On a semi-flushmount, there is a stem of sorts and the "rim" is dropped down a few inches from the ceiling. Sometimes you can put a higher wattage bulb in this style because the heat can escape, and you get the bonus of bouncing light off of the ceiling. Flushmounts have the advantage of being less obtrusive; might be better in a hallway. Semi-flush might be better in a foyer or over an island.