The 10mm has a lot going for it. As a 1911-sized cartridge, the only competitor is the .45 Super, which in addition to having ammunition more expensive and rare than the 10mm, will require a spring configuration seperate from that specificed by the .45 ACP.
200+gr bullets launched at 1200 fps are the current upper limit on service sized pistols. While this level of performance can be equaled by .357 revolvers, it is more easily approached by larger caliber autoloaders. Amongst those sidearms, the 10mm offers what I consider the greatest versatility. It's cartridge capacity is superior, in both single and double stack, than the .45 ACP. +P .45ACP can approach full-power 10mm loads, but not by remaining inside SAAMI specifications. 10mm runs from 135 gr to 200+ grain loadings, an accomplishment previously offered only by revolvers.
The semiauto offers reduced recoil at the same power factors compared to the revolver, in addition to increased capacity. Granted, the 10mm will never offer the upper limit capable with full-pressure .41 Magnum ammunition. These advantages are often mainly applicable to large game hunting, and not nessicarily to self defense.
Factory pistols chambered in 10mm are currently offered by Kimber, Dan Wesson, Glock, and EAA. While lacking the availablility offered to those who prefer 9mm or .45ACP, a sufficient variety abounds to select a design satisfing all a but the most demanding of afficianados. Discountinued designs such as the Smith and Wesson autoloaders increase the variety of possible design, as do the various reworked H&K USP and ParaOrd models.
For these reasons, I chose the 10mm as my primary defensive pistol ammunition. In the autoloading 1911-platform that I prefer, I can achieve 8-10 shots per magazine, have a 200+ power factor, and have access to factory ammunition at the 200+ power factor level that I prefer for the lowest overall price of gun and ammunition.
My first pistol was a polymer framed double-stacked 9mm, my second was a steel-framed single-stack .45ACP. In no circumstance would I feel underarmed with one of these compared to any 10mm. My most recent acquisition was a 10mm. Even with only a small measured advantage that I consider it to deliver compared to "traditional" ammunition I'll always treasure that increased performance that I consider it to deliver versus its competitors.
Put another way, "Yeah, it's not the same, but the joy of life is in the differences!"