Ichiro said it very succinctly.
"light gun + small grip + heavy trigger + short barrel = difficult for me to shoot accurately."
Some subjectivity is always likely when answering questions like this, and it really depends on your perceived needs and desires ... but here's my thoughts regarding the potential disadvantages of an Airweight DAO J-frame ...
Small grip frame.
Heavy DAO trigger stroke.
Short sight radius & difficult-to-see notch & post sights.
Light weight and higher felt recoil than steel-framed models (but less harsh than the Airlite models).
These attributes can potentially make it more difficult to consistently and accurately place shots where intended, even under 'ideal' range conditions. Small framed revolvers can require a higher level of knowledge and DA revolver shooting skills than when using larger framed models.
The weight of the standard Airweights can be an acceptable compromise, depending on the owner's abilities, as well as the ammunition used, of course.
The 23 oz. weight of the 640 can be noticeably heavier than the 15 oz. weight of the 642, but the shorter barreled 60 is half an once lighter than the 640, and the steel .38 Spl 36LS weighs only 20 oz. You can also reduce the weight of the Airweight by something close to an ounce if you install the Bantam grips, too (snap-on, no screw).
Now, while most folks agree that +P ammunition results in more felt recoil than standard pressure ammunition ... there's +P ammunition, and then there's +P ammunition.
I've used some Lawman 158gr TMJ +P loads for qualification that exhibited noticeably more recoil than the similar weight Remington 158gr LHP +P loads I used for actual carry (I'm lazy and like to avoid cleaning lead out of the charge holes
). For the most part I've found the Speer SB 135gr +P loads to offer more recoil than the Winchester or Remington 158gr LHP +P, too.
Some folks don't mind +P ammunition (in those models rated for a steady diet of +P), and some folks would rather use standard pressure ammunition for the controllability advantages.
I've seen some decent LE pistol users ... who apparently entered LE work long after revolvers were the issued service weapons, and revolver skills were taught ... bring a newly purchased 5-shot snub-nosed revolver to the range for qualification and be rather surprised when they couldn't shoot it very well at first.
Of course, I've always suspected that average revolver shooters could be more easily transitioned into pistols shooters than the other way around. Doesn't mean they'll like pistols, and I've heard some real grumbling from old time revolver shooters ... but I've also seen their scores improve when they applied their revolver trigger control skills and use of sights to their pistol shooting.
When I first bought my 642-1 I spent some focused range time with it, and with a couple of 442 & 640 range training guns, running through several hundred rounds to knock the rust of my revolver skills. (Ditto my DAO revolver skills with my SP-101 .357 Magnum, using full power Magnum ammunition, too.)
I finally reached the point where I could run my 642 through any of the various service pistol qualification courses of fire and qualify Master with it. Took more reloading, granted, but I also knocked the rust off my previously well-used speedloader & speedstrip skills, too. I keep my DAO snub revolver skills fresh, and include often include drills from 'precision' (head) shots on silhouettes at 25-35 yards (not practical, most likely, but it requires focusing on the basics), as well as making called hits on wooden clothespins at distances of 5-7 yards. That takes some focus on basic skills maintenance, which is why I include it.
Now, what's a bit odd is that over the years I've found I can shoot my J-frames better than my short-barreled SP-101, even when shooting .38 Spl loads from the Ruger. I guess I've become accustomed to the DA/DAO trigger strokes of my various J-frames.
Lightweight, easy to carry in various manners, chambered in a reasonably sufficient defensive caliber, reliable ... and the revolver is less prone, or perhaps just less susceptible, to 'limp-wrist' grip issues than a diminutive pistol platform. If the cylinder can rotate when the trigger is pulled, and the hammer can fall, the round under the hammer can fire ... all else being normal (good ammunition, clean and well maintained revolver, etc., etc.). I wouldn't necessarily include the Airlite models in this category, since bullet jump concerns may arise, depending on the ammunition used and the individual shooter.
I like the steel J-frames for shooting ... but I like the Airweights better for carry and shooting.
Different strokes. Different handguns for different folks, too.
