I never fly in anything but idle up anymore. When your helicopter balloons outside during regular forward flight, you'll be damn glad of that negative pitch. Nearly killing throttle to bring the helicopter lower is a good way to lose control for an inexperienced pilot. I'd say move up to idle up as soon as you can figure out how to program and use it.

Keep in mind, that typically, crashing when in idle up mode causes alot more damage than crashing in normal mode, since the blades go in under power. If you're a quick thinker during an emergency, you should try to remember to flip that idle up switch back up to go back into norm mode if you know you're going to crash so as to avoid damage.