.44 spl. vs. .44 mag considerations for guns with 3" barrels:
For defense, I like heavy-for-caliber bullets pushed at good velocities from fairly short barrels. These specifications tend to work against .44 special.
For consideration of a 3" barrel N-frame model, I would definitely pick the .44 mag 29/629... not because I want to shoot full-house .44 mag loads... in fact, I don't enjoy shooting those at all. I would choose it to be able to make loads which are HOT by .44 spl. standards and MILD by .44 mag. standards.
Part of this is related to my preferred barrel length which, in these guns, is 3". So for me, the problem with the 24/624 is that with a barrel length of 3", the .44 spl. case has to be loaded pretty much close to or at maximum to develop decent velocity. That's working the cases and the gun pretty hard, harder than I would prefer to work them. Remember too that with a 3" barrel, it's better to use faster powders which can create their power without relying on a long barrel. This puts potent defense loadings for a 3" .44 special at or beyond maximum pressure.
It isn't that a .44 special load is incapable of defense duty, far from it, especially if you're working with a 5" or 6" barrel! But this caliber's hands are tied pretty tightly for use in short barrels.
If a 29/629 3" is selected instead, it's possible to make .44 mag loads which are right at or just beyond the maximum load for .44 spl. but still well below the maximum .44 mag. power, without working the cases or the gun very hard at all. And you can also shoot mousephart .44 special Cowboy Loads in the gun for really light shooting pleasure.
What I'd consider an excellent defense load with a 3" .44 caliber revolver (very effective, yet still quite managable) is a 245 gr. Keith-style cast bullet travelling at about 900 fps, yielding 440 fpe. This is considered a "starting" load by .44 magnum standards, but well beyond maximum by .44 special standards. This is the reason I would choose to buy a 3" 29/629 over a 3" 24/624. Certainly you could buy a 24/624 and a 29/629, but I see no need to buy nearly duplicate N-frame revolvers when the 29/629 can do it all.
In fact, I did just buy a 629 3" which I'm expecting to arrive in a week or so. Now I need to figure out a good defense load for my 696!