I, too, load on a 366. The issue with the new style Winchester hull is with the hulls, not the 366. Hornady makes a straight walled crimp die that helps with them. And the primer depth issue can be eliminated with the optional spring loaded priming die.I've been loading on a 366 for over 20 years now and really like it. It is a heavy duty machine that turns out consistent reloads. You can tailor your crimps just so--I put a nice taper on the ones for my semiauto shotguns. A sleeve bushing is available that will let you use all your MEC powder bushings. The negative is that it is not as "tolerant" as a MEC 600 to various hulls. With my MEC 600 I can load Remington, Winchester, or Federal hulls with no adjustments. With the 366 you'll likely have to make changes for primer depth and crimp. It also took me a long time to get the crimps on the new Winchester high strength hulls just right.
I usually load a run of at least a thousand shells on the 366 and still use my MEC 600 for short runs of hunting loads. Hope this helps