I have had a problem, but it was easily fixed and just required some attention. If you tighten the powder measure screw that is on the side of the measure and holds the bar arm onto the bar too tight, your measure will not fall back down with gravity. That means that the case is already out of that hole when the bar comes back, spilling powder all over the place and screwing up your charges.
Now my screw is too lose and sometimes the pin that sticks in that little plastic thing on the side of the bar comes lose and the bar will just sit there as I continue to cycle the machine. This resulted in me loading a bunch of ammo without powder! That was bad especially when I found out on the 600 yard line during my NM Course.
You can get some really accurate loads with the measure if you just pay attention and keep consistancy. The other thing I try to do is screw the powder bell down enough where the powder bar goes all the way over to the end of the measure so all of the powder gets pushed out of the cup.
And finally, if you buy a AT 500 powder die and powder funnel, you can replace the auto-powder measure and scale measure your loads and then dump the powder down the funnel. I have found an easy cycle for this that lets me load extremely consistant loads in a relatively short amount of time because I can still prime, powder charge, seat, and crimp with one crank of the handle.
So go for it, and good luck.