The best progressive reloader?
I think it depends on what you plan to do with it. Or, perhaps, how much you plan to use it, or how many boxes/flats you plan to load with it at one sitting.
I, like most here, started with the MEC. It is true, as Calkid says, that a MEC is easy to adjust. However, in my experience, that's what has to be done way too often for me. I never, ever, got through reloading a flat of shells on any of the three or four 12ga MECs I have owned without having to stop and adjust something. They always needed some tweaking, some change, some something.
I went to the Dillon. Fastest, short learning curve, makes great shells, and, did I mention fast?
I've had three Dillons, had two at the time I purchased my Spolar (one set up for 12, the other for 20). I loved them, but as much as I load (I almost always load a flat or two at one sitting, sometimes more), my old elbow got so sore I had to stop.
I sold them and purchased a Spolar. No adjusting, just place the hull in, add the wad and up and down the foot pedal. Almost as fast as the Dillon, and no pain. I bought a gently used Dillon as a "back-up" a year or so after purchasing the Spolar, but it sat unused in my garage so I sold it a few months ago.
Anything ever break? Yeah, after about 105K (I bought it in October, 2008), the whatchamacallit that vibrates to settle primers/powder gave out, burned out or just quit. I sent the part to Spolar and had it back, fixed, in about a week.
Still works great at almost 130K.
I've never loaded on a P-W, but two shooting buddies have them (the model preceding the Patriot) and one gave up on his, the other has had numerous problems and has sent his back at least once to get it to load properly. I really don't know all the details, and maybe they should have called Whiz first, but neither are big cheerleaders for P-W.
I like my Spolar, but I load a lot. If I loaded 5 or 6 boxes a week, maybe I'd just stick to a MEC. But for a lot of shells, the Spolar or Dillon work great.
Bob