This ^^^^ times about a hundred. I've had both and now have a couple of 750s. In hindsight, my 650s were actually better machines (with all the standard addons), and produced more consistent ammo, especially once they were all dialed in. The 650 primer system, while more complex and a huge pain to swing sizes, was really bullet proof once it was dialed in. My 750s are great machines, but require learning an entirely new set of little tweaks and such, and while their primer system (basically a slightly modified version of the 550 primer system) is easier to swing, it is also a bit more finicky. That said, most of the tweaks, tuning, and adjustment one learns with the 550 applies to the 750 priming system. As far as reports of people breaking the index ring on them......I personally think that has to be mostly operator error. I've got easily over 50K rounds on 2 of them, still on the original index rings. I think people force them when something isn't quite right and that's what causes the breakage. I do go through some primer op rods though. It seems that if you adjust them to get 100% primer bar extension, then the elbow rests on the pulley, and after about 10K rounds or so, the rod breaks there. You can adjust it off the elbow, but then you risk it not picking up a primer every time as any slight disturbance like spilled powder might keep the primer bar from going all the way back. Dillon says their new op rods are hardened more, so we'll see. For now I just have a lot of spares on hand;-) My 650s didn't have grease fittings on them either, so you did have to pull them apart to clean and lube now and then. The 750s have the grease fittings, I just hit each one with one pump from a mini grease gun about every 5K rounds or so. Basically, if someone were to ask me today if they should upgrade a 650 to a 750, I would say nope, you aren't really gaining anything. Better use of money would be spending the 80 bucks or whatever it is now and shipping your 650 to Dillon for the refurbishment program...or getting a 1100 or 1050.