I agree - experiences seem to vary, sometimes by a lot.
The only experience I've had with a fairly long cone, is with a local fellow's rifle. Due to the long bearing surface (drag) gentle tapered cone dragging on the cloth patch, the effort to load a tight fitting ball and patch, became almost impossible for LB. I gave him some of the .400" sized balls I was loading, and he had great difficulty loading them in his .40 cal. rifle.
They same balls, VERY soft lead, were easy to load in my .40's short rounded crown however, even though that barrel had a tight bore, 002" smaller than the ball's diameter. I was using a .020" patch as well.
At one time, I coned the bore of my .45 long- rifle, a short cone for a depth of 3/4" long. Not until I cut off that portion of the muzzle and re-crowned it normally(for me), did my accuracy return. Some people report improved accuracy, though. I cannot argue with that, however I can and do print my results.
To explain this phenomenon of a coned muzzle requiring more difficulty than a short crown, one only has to read the teachings of Corbin about bullet and brass drawing/sizing. The drawing angle inside the drawing die is very short and is smoothly radiused, just like the crowns I & now Taylor put on our muzzleloading barrel crowns. The rounded crown, radiused I call it, we put on our barrel muzzles, is less than 1/8" long or deep, yet they allow loading with tight combinations. Accuracy is likely not as good as it could be if a false muzzle was used, however false muzzles do not belong on trail walk or hunting-type rifles, in my opinion.
Hungry Horse makes a very good point. If the coned muzzles or any other sort of crown shape increased accuracy and made loading tight combinations easy as well, false muzzles would never have been invented.
The very best muzzle shape is a square edge - SHARP, or an 11 degree angle inward (almost square) as now preferred by the stool shooters. These shapes give the 'perfect' delivery of the bullet or patched round ball. Since we cannot have that 'perfect' shape as we need a muzzle shape that allows us to load our rifles, yet still gives good accuracy, we must test to find the 'best' shape for us. We are the ones who need to be satisfied.
The accuracy you demand or want from your barrel is the final test/criteria. Some crown shapes are more accurate than others - what satisfies you is right for you.
I tried LB's barrel for my self as I'd been told the cone was easier to load and he was right, the long cone was more difficult to load than my own radiused, short crown.