I vote K&M w/gauge
It is completely unique
I have K&M's without gauge also Sinclair and you can adjust both for seating depth. I have one K&M for each case size I load for easy for me to keep track of seating depth.
Correct primer seating is not about feel or fit or looks.
It's about setting every primer(brand/type) to an exact condition -that your gun shoots best with. You cannot achieve this by feel, nor without regard to temps, pocket depths and striker operation/settings. This takes testing, measurements, and more testing.
Now everyone knows that fully seated primers usually go off. And everyone knows the point blank BR boys just squash em into pockets with no measure of it whatsoever. They go off as well.
But unless you limit to tiny 6PPCs at extreme pressures, you need to understand there are things that can go poorly for you with this approach. Or, just as bad, your primer seating can cause you to waste a bunch of load development efforts, and end up choosing loads that are not actually the best. You could choose a primer that 'seems' best(or better than the others tried) while missing that the performance variance was never about a particular primer at all.
I'm saying you can get the correct type of primer to bring the best out of a load no matter it's brand. As well, you can make good primers seem less than right for your gun.
A lot of it follows the common notions that primers are just a matter of trial & error brand/type swapping, and that abstracts in seating(like feel) are good enough.
I discovered otherwise a hard way, and there have been BR shooters who've found it(hopefully easier than I). Sometimes it's addressed with firing pin mass/spring/protrusion settings, trigger brand/hanger settings/action timing, and all of it ultimately falls(or rises) to consistent primer setting.
The K&M does feel good enough. But anyone using a gauged K&M knows that feel is meaningless to actual setting. It's really analogous to seating bullets by feel(rather than measure).
And THIS is what makes the gauged K&M incomparable to ANY other.
You can't adjust the Sinclair for seating condition(i.e. 2thou crush).I have K&M's without gauge also Sinclair and you can adjust both for seating depth.
You can't adjust the Sinclair for seating condition(i.e. 2thou crush).
There are also priming tools that set the primer x-amount below the casehead. This is nothing near what the K&M does.
What a luxurey! Two of them. When I'm at the range my K&M resides in my back pocket, and just couldn't live without it. I may opt for the dial indicator setup one day. I have arthuritis in my hands pretty bad these days and the Sinclair and that stuff just didn't get along very well.
Gary, at 70 my hand aren't the best either one of the reasons I have one for each case head. I think over the years they finally got broke in and pretty easy to seat a primer or it could be the Celebrex I have to take.
I have deep arthuritis in both of my thumb joints. The left hand has almost no feeling in that area these days. But on the other hand the K&M seems to fit my right hand perfectly, and this really helps me out. I'm blaming my issues on the U.S. Government in 1968 when they told us Agent Orange was bug spray. I will never forgive them till they day I'm cold and in the ground.