You can either buy pre-loaded APS strips, or you can load them yourself. You can NOT buy pre-loaded primer tubes.
I can load up four APS strips in about the same time it would take me to hunt-n-peck them into a primer tube. And, when I'm done, I'm 100% positive that all the primers are oriented the right way, and I'm not going to wind up with any rounds with a primer loaded backwards... because I can SEE them in the strips, and verify that everything's correct.
I have tow RCBS Pro2000 presses, with the APS primer system. I also have a Hornady LnL AP. The LnL gets used strictly for case prep tasks - all my loading is done on the presses that have the APS system. I just find it more reliable - requiring considerably less "tweaking" than a tube-based primer feeding system, and changing from small to large primers is literally a 30-second task.
In addition, when I have to hand-prime, it's either with an RCBS universal hand priming APS tool, or more recently, with their press-mounted APS tool (better leverage, and less fatigue on the hand after squeezing 100 primers).
In short - yeah, I'm a big fan of the APS system, and haven't had any issues with it in the 6 or so years I've been using it.