The cons of the stoney point is putting the red holder on and off your calibers. Can be off up to .005" I have a set of calibers I keep it attached to, but even changing out the end piece (for various calibers) things can change.

The pros, is I find it great to use. helps me troubleshoot problems, like headspace. Helps me setup my dies correctly. Helps me setup my bullet seatin depth the same every time.

Only other is sold by sinclair intl.