Reloading is a black hole like a boat! Next thing ya know you are casting your own bullets. I do it out of self defense as a result of shooting competitions. A few years back when ammo was both plentiful and reasonable my Dillions sat dormant for the most part as my time had more value. In todays landscape they are all fired back up and rocking! In essence the guy selling the 550BL has all the options to make it a dressed up 550. I have both 550s and 750s both are workhorses. While I like running the 750 due to speed the 550 is a bit more flexible and forgiving. When I teach reloading classes I always revert back to a single stage to teach the basics. Reloading is therapeutic for me. And there is something deeply satisfying about creating your own ammo.