The most common gotchas is trying to pull an APS strip out the wrong way. RCBS warns, but not everybody has the best direction reading skills. You will break it. Yes RCBS will shoot you new parts free in a couple of days, but why go through that....just be warned and don't.
Also, since every time you move the press handle into the primer seating area...that is moving the handle toward the bench at the bottom of a stroke, you press a primer up past the strip it's mounted in. (case present or not) That means, unless you finish the stroke and set the primer or push it all the way out, it can jam the strip and make it refuse to index or even pull out.
While that sounds bad, the fix is simply to push it back in with a .223 bullet, or any other thing you have handy the same diameter as the primer hole....an Allen wrench, a pencil eraser, a dowel, tinker toy, whatever. Just keep such a thing handy for both sized primers. Try to force it and you will just be taking the primer feed mechanism apart.....so don't.
While that all sounds like a pain, it's just a tiny learning curve and APS, once learned, is well worth it when you buy a year supply of preloaded primers, and enjoy speed and safety not possible with tube loaders.
One feature the Pro 2000 doesn't have, is a way to take the primer advance off line, without having to remove the whole strip. Like, for example, if or when you screw up a powder charge and want to feed a primed case again. You can shape a Popsicle stick to stick in and stop the advance or you can make a more elegant and convenient advance stop by copying my APS mods found in AR15's tacked gateway thread.
HERE.
I have other "mods" in the "gateway" thread as well if you're interested.
My forum name there is GWhis.
If you reload a lot of pistol, you will eventually want to get RCBS's new powder-through expanders, and extra case-activated lower assemblies (powder dies & brackets) for each caliber, so you can make changing calibers using one Uniflow silly fast.
Have fun with your PRO-2K! Great press. Very versatile and simple. Once you get it set up....it doesn't go out of sync.
More questions? Just ask.