I am still learning the unit myself, but can say I am extremely happy with it. My first screwup was not realizing how the airflow setting worked and having very poor atomization. Then I figured out or remembered can't remember which how to adjust the pattern size. That was when it really started working better for me.
I bought all the needles, and have yet to use anything but the one that came with it. I do recommend the small cups and whip hose, but the gravity conversion kit is something I wish I hadn't bought.
Good luck with it and please share what you learn with it as well. Mutually, I am glad to be able to tap someone else with the same unit for questions/opinions!