I have an older RCBS 2000 progressive press that I used to load many thousands of rounds of pistol caliber ammo for IDPA and Cowboy Action. Sadly this press, with its innovative APS strip priming system, is no longer made.
With this system, primers are held in plastic strips, which advance horizontally. So there are no columns of primers, stacked one atop the other (where they could cause a chain reaction).
I believe that APS priming was a superior, safer, easier-to-change system and that RCBS should bring it back. APS is certainly SAFER, plus faster to change from large to small primer types. WAY faster.
Before I purchased this RCBS 2000 press, I tested Dillon and Hornady progressive press alternatives extensively. At the time, many serious progressive press owners had TWO Dillons because it was such a PIA to change primer set-ups from small to large (or vice-versa). By contrast, I could switch from large to small (or vice-versa) really easily in under 5 minutes.
I also concluded the RCBS and Hornady powder measure systems were considerably more precise (and trouble free) than the Dillon system with the sliding bar. I did quite a lot of testing to confirm that. The difference was quite noticeable with extruded powders.
I do recommend that anyone using a progressive press run a
lock-out die if you have enough stations. This stops the press from advancing if the powder charge is too high or too low. My lock-out die did "save my bacon" a few times.
The lock-out die can be used on Dillon and Hornady presses as well as RCBS progressives.