Since I read all the way through this, I guess I will put my 2 cents in also.
I have owned one 10mm and still do, a 610 S&W. It was a first run 5" that I had Ron Power shorten off the back to a 4" to fit common N Frame duty holsters. I have owned several 40 S&W auto's, an EAA Witness, a 4046 Smith & Wesson, a couple Glock 23's, and my current one a Springfield XDm.
Of all the 10mm auto pistols that have been offered that I consider carryable the Glock 20 and it's compact little brother are the only one that are double stacked. Hi Capacity is nice when you really need a handgun. On the other hand the Glock grip is a little large for my liking. That said the Glock is the only 10mm Auto I would consider owning at this time other than as a collectors piece.
The Delta and S&W 10mm auto's will last much longer on a diet of 40 S&W velocity ammo from everything I have read and heard about them.
Several years ago I bought up samples of all the 10 mm and 40 S&W carry ammo that I could find at the time, and tested it. My findings were quite a surprise. A great deal of the 10mm ammo was factory down loaded to 40 S&W velocity. I even tested some that was running slower in 10mm than it was in 40 S&W. If my memory serves me correctly I think that Silvertips and Corbon were about the only ones tested that were faster than 40 S&W by any meaningful amount. My guess is that the manufacturers put the weak on the 10mm first to keep from trashing out Deltas and S&W auto's.
I like my 610 a great deal. Most of the ammo I run through it is 40 S&W speed lead reloads. Why is that?? Most of my shooting is at paper in matches. I do not need the recoil and blast of full house 10mm killing cardboard. Another issue on steel the 10mm with full house ammo is likely to do damage to the targets. I read above that the 10mm was between a 9mm and 45acp in stopping power. Obviously the person who stated this has never shot full power 10mm reloads.
I have carryed the 610 as a primary duty weapon, and liked it very much in that roll. Why ?? As a Deputy Sheriff in rural Missouri most of the shots fired are expended finishing off deer that have been hit by cars. Full House 10mm does a better job killing deer than the 40 S&W in my experiance. Did I feel under gunned in case of a gunfight? NO, I shoot a lot, and I carried 4 Full Moon clips in a Quad Speed Loader Pouch at the time. In the winter I would have another 4 full moon clips in my jacket pockets.
Personal Protection: a 10mm while not a 41 Magnum, is close when handloaded to its potential. Like the Alaska Fellow pointed out, in Bear and Moose Country a Magazine Full of Full Power 10mm could save your bacon.
If I had a choice between a Glock 20 and a 629 for bear country, I think I would go with the Glocks firepower, and the ability to reload it with another large amount of ammo quickly and get it back in the fight. The 629 with 6 shots and quite possibly a hard time reloading it under REAL Stress might take a back seat to the new fangled auto. If I lived in bear country I would have to evaluate this situation much closer.
The 40 S&W while not as powerful as a 45 acp, is close. The 10mm with ammunition funning meaningfully faster than 40 S&W will generate recoil past the ability of most Law Enforcement Officers to comfortably handle. In the hands of someone willing to take on handling the blast and recoil of a 10mm, it is an awsom weapon. Both the 40 S&W and the 10mm auto have a place. I certainly hope the Glock 20 keeps the 10mm alive and well.
