it is about fit and finish, and there are some nuances of how some of the various die brands work, so - personal preference. this thread might be more valuable if it morphs into why people prefer one brand over another, or - say, for single stage, turret, or progressive press use. I just use an old singe stage, so - all the same to me there, but think there are nuances people prefer for different uses. for whatever reason I kind of like the floating Hornady seater stem, but - no idea if it actually work better, but it makes sense it would help keep the bullet aligned as it feeds up into the die. RCBS in my few expreiences, has just sent me pieces when I got stuck and asked them a few questions, they just sent me differerent expanders to try them and I didn't even ask, so - was pretty impressed with that.