I'm somewhat of a "late adopter" of things. P-mags were out for years before I bought one. I just got my first striker fired anything a couple years ago. I just finally powder coated a bullet a couple weeks ago.
I'd never tried an M-die, despite the overwhelming supply of positive remarks. I've been content with the expander plug on my Dillon measures & the Lee universal for single stage work. They do, after all, get the job done.
That said...
I decided to finally go ahead and add one of the expanders from NOE to a recent order, the ones that replace the plug in the Lee die. I used it to help prep some 300 Blackout brass to receive some TL314-90-SWC's (because I want to be Larry Gibson when I grow up).
It's a night & day difference. Far easier on the brass itself, obviously. Also, the claims of how much easier it is to keep the projectile straight with the brass, not at all exaggerated. I'll be ordering a few more of these immediately.
I know MOST of you are past this point, and already on the M-die bandwagon. Hopefully someone that's considering, but hasn't yet tried one, will read this a give it a shot.