Thirty years ago, double action revolvers were highly favored for defense, being relied upon by law enforcement and civilians alike and they proliferated the market. Then came the age of the high capacity "Wonder Nine" and the trusty old revolver became a relic of the past, more suitable, in the eyes of many, for the novice rather than the skilled "operator". But double action revolvers have not faded away and they remain effective and versatile defensive weapons.
Those who criticize revolvers point to limited capacity, high bore axis (which renders greater perceived recoil than many semi-automatics), heavy double action triggers, bulky profiles, and slow reloading. They may also continue that extractor rods can loosen to bind actions, that revolvers shoot loose and get out of time, and that (at least in theory) the lock work of revolvers have more moving parts than semi-automatic pistols which makes them more likely to fail in adverse conditions.
While there is merit to these criticisms, semi-automatic pistols are not without issues. Double feeds and stove pipe jams (both of which are often caused by shooter error such as "limp wristing" and unseated magazines) can bind actions, a bad cartridge can momentarily stop a semi-automatic (which leads some to promote double strike capability), and damaged or lost magazines can compromise reliability and curtail function. Moreover, the service life of most handguns is finite which means that after so many rounds, they will require the attention of an armorer.
Proper care and maintenance, understanding the design and the limitations of your defensive handgun, and practice and more practice can eliminate the majority of criticisms that can can be directed towards both revolvers and semi-automatic pistols, making them more academic than practical. On both sides on the aisle, some designs are more fragile than others. Many extoll the virtues of the Glock which has a well deserved reputation for reliability and durability, yet the Ruger GP 100 and the larger Redhawk offer similar qualities and may well represent the current pinnacle of evolution for double action revolvers.
What does the archaic, double action revolver really have to offer in the world of high capacity semi-automatics and rapid magazine changes? We could enter the land of the theoretical and say that as long as a handful of cartridges remain, the old revolver will keep shooting long after magazines have run dry. We can point to custom grips, such as those offered by Herrett's that make the revolver truly fit the hand of the shooter. We can indicate that revolvers are strong enough to handle the most powerful handgun cartridges in the world while semi-automatics are typically not and we can note that the fixed barrel renders accuracy that far exceeds the "combat accuracy" offered by many semi-autos.
But, the real virtue of the revolver is the combination of sufficient capacity (yet and still, an average of 2.5 rounds are fired in defensive situations), simplicity of operation (just open it, load it, close it, and pull the trigger), and substantial versatility. Since revolver cartridges headspace on the rims rather than the case mouths, overall cartridge length does not affect function as long as the cartridge fits in the chamber. Since revolvers do not have feed ramps, bullet profiles do not interfere with feeding. Since revolvers do not have slides that are dependent upon recoil springs, low chamber pressures does not cause revolvers to fail to cycle.
Thus, a revolver can be loaded up or down for specific applications without the necessity of changing barrels and/or recoil springs. This provides a field day for the hand loader (who is also gratified by not having to crawl around on the ground to recover his brass) but it is also useful for those who only use factory ammunition. For example, one who chooses the well proven .357 Magnum for defense can reliably shoot lower cost, milder mannered, .38 Special cartridges for practice by simply loading them in the chambers. Similarly, one who chooses a .44 Magnum for the field can use less powerful .44 Special cartridges which are more suited to defense against human attackers.
Of course, there are trade offs when you choose one handgun over another. For many years, six rounds of .357 Magnum ammunition in the cylinder and two loaded speed loaders (or a total of eighteen rounds) was considered adequate for most defensive applications requiring the use of a handgun. Although many now seem to feel unprepared without 45 rounds of .40 S&W at their disposal (which is five more rounds of ammunition than was held by an infantry cartridge box during the War Between the States) the double action revolver still provides capable, reliable defense with exceptional versatility that does not require purchasing and changing parts.