I chose a 642 because it was noticeably lighter than my 649.
I don't like titanium cylinders, even though the do offer a slight further weight reduction.
The trade-off is that my lighter weight 642 offers more felt recoil than my steel-framed 649. Is it more than I can tolerate? No. Is it more than I desire to tolerate for range practice? Again, no ... not under normal conditions and for a reasonable length of time and for a reasonable number of rounds ... and I'd have to say that a Scandium J-frame chambered in .357 Magnum, loaded with Magnum ammunition, is awarded the honor of offering more felt recoil than I personally care to tolerate.
I've demonstrated that I can accurately fire a 3-round rapid-fire string on a regular qualification silhouette, at 10-yards, two-handed, using an Airlite .357 Magnum J-frame, using full-power 125gr Magnum defensive ammunition ... but it wasn't exactly what I'd consider an enjoyable experience.
50-100 rounds of +P ammunition can result in the bottom of my index finger's last knuckle being 'hammered', however, and I'll feel it for a day or two. It's the inside/bottom of the trigger guard rising into the bottom of my index finger that causes the discomfort, but that's really only a problem for extended range sessions with +P ammunition. Standard pressure ammunition doesn't cause me similar discomfort, and it's not something that would really concern me an 'actual' situation, anyway ... where I'd be more concerned about potential hearing loss or eye injury. (The
real world can be an unforgiving place, you know.)
The thing to consider about diminutive 5-shot revolvers, though, is that their safe and effective use generally require a higher level of DA/DAO revolver skills and techniques, even among many users/shooters of medium and large frame revolvers. The smaller grip dimensions, heavier DA/DAO triggers, shortened sight radius and basic fixed sights and lighter overall weight are often "less-than-advantageous" for some folks.
I've seen a few folks who are otherwise competent full-size revolver shooters experience issues ranging from discomfort to serious skills, accuracy and safe manipulation issues when switching to snub-nosed revolvers. Even something as 'basic' as the wrong grip can result in a mangled thumb tip (hitting the cylinder latch, rear of the cylinder or even the recoil shield edge) or an injured finger (hot gasses escaping from the cylinder/barrel gap, at the least).
Whenever someone asks me to recommend a 5-shot short-barreled revolver for an "off-duty" weapon, and I learn they've never actually shot one, I try to have them shoot one, either mine (if it's with me at the range that day) or one we keep in the training safe. Better to find out that they may not be willing to devote the additional training & practice time often needed for the little wheelguns, or simply aren't interested, before spending the money and discovering it the hard way ...
It's amazing how quickly some people change their minds once they actually shoot one, especially an Airweight loaded with +P ammunition, but I prefer to introduce them to the platform with standard pressure ammunition, and then if they're still interested ... and interested in higher pressure defensive ammunition ... I'll have them shoot some +P loads.
Fortunately, S&W offers enough model variations in their J-frame line, ranging from all-steel to one of the Airweight/Airlite models, to probably satisfy the needs of most folks who might desire a 5-shot j-frame. There are some potential ammunition concerns and restrictions once the Airlite models are being considered, in regard to both potential bullet-jump and gas erosion of the titanium cylinders. This issue is addressed in the owner's manual, on Page 14 ... 1.97 MB file which downloads in Adobe .pdf format, if your connection isn't fast ...
http://www.smith-wesson.com/wcsstore/SmWesson/upload/other/Revolver.pdf
If your local ranges don't have a 442/642 available for rental, you might look for another range, even if farther away. Do either of your local ranges at least offer one model or another of an Airlite for rental? An Airlite is lighter than an Airweight, and if anything might offer you an example of some increased felt recoil, compared to how it might feel in an Airweight, when used with +P ammunition.
You really ought to find some range where you can try out the different J-frames. Maybe a range safety officer might have a personally owned Airweight he/she might be willing to allow you to test-fire, while attentively hovering nearby, of course.
Personally, I find shooting my compact and subcompact .45 ACP pistols to be "easier", in some respects, than shooting my J-frame Airweight loaded with +P ammunition, but it's not really a comparison I'd feel comfortable using to describe shooting those platforms to someone who hasn't shot both platforms themselves. Too many subjective considerations which can get lost in translation.
FWIW, once I dusted off my DA/DAO revolver skills, and refined them a bit, my 642 became my most frequently carried off-duty weapon for reasons of overall size, convenience of (safe) carry methods and falling within my personal range of acceptable defensive calibers. I can carry it when I can't as "easily" carry one of my subcompact 9mm/.40 S&W/.45 ACP pistols, if only because of preference of attire and personal comfort in warmer weather, during casual activities.
Not everyone may feel that way.
Personal risk assessment, research, experience and informed choice is very important, you know.
Ya know? A .357 magnum from a 2" barrel generates some fire and bang. 
).
