I carry a 29-10 Lew Horton Special with 4" barrel, just because I can.
There are two important considerations, for me:
1. Holster. It's heavy and needs to be well supported. *I* like the Galco CM126B Combat Master Belt Holster. Snug fit, firm without digging into me.
2. Ammo. Full-spec 44 Magnum ammo is way too hot for self-defense use in a 4" gun, I don't care WHO you are. The kick, recoil and muzzle blast make follow-up shots slow and difficult, and may give you pause even on the first shot. Of course, if you're close enough to your target, you can burn them to death with the blast.
That said, I do like Hornady LeverEvolution 44 MAG 225 GR FTX ammo, and Federal Cartridge makes the PH44HS1 Hydra Shok, or P44XB1 Barnes Expander total copper bullet with a deeeep cavity, that I find controllable in the 4" 29.
My preferred self-defense round is the Hornady 44 Special 165 gr FTX Critical Defense. Quite manageable, and highly effective. I keep them all on hand.
Another caution: big booletts mean more heavy stuff to distribute around your body, and another deterrent to reloading under stress.
Also keep in mind that such a large, heavy revolver will almost certainly be slower to bring into action than smaller ones, or autos. Soooo:
How do you get to Carnegie Hall? Practice, practice, practice - - -