I'm sure someone will disagree with me, but in my experience....the training gear was necessary and it paid off quite well. The training gear allowed me to get familiar with what's going on and how the heli will react. I've heard that the training gear will vibrate while flying and it will mess with the gyro. After seeing what my 500 did with training gear, I do believe that the vibes from the training gear do effect the gyro.
That all being said, here is my opinion....keep using the training gear as much as you feel is necessary. You stated, above, that you are using the training gear for nose in hovering. I don't think that's a dumb idea at all. Nose in is very difficult in the beginning. I would take the training gear off as soon as you feel comfortable and no sooner. You are going to have good days and bad days, and that's just the way it is. Play around with it....take advantage of the fact that you have the training gear and get use to your nose in hovering and how the heli will react to your stick movements. Once you are comfortable and confident, go ahead and take the training gear off and prepare yourself for a better flight. Without the training gear, the heli will react quicker and more smoothly.
Just do yourself a favor.....stay on the training gear as long as you feel is necessary. It's your heli. It's your money that will pay for the parts when you "dumb thumb" it (and you will dumb thumb it someday, we all do). So, go at your own pace and you'll figure it out. I have no doubt!
Good luck buddy!!!