You should be able to get better than 9-10" of penetration. FBI standard requires 12"+ and I would think a .44 SPL could do that with a 200 gr. bullet.
For those who have problems with using handloads for carry, Wichester is loading SilverTips for the .44 Special and CCI loads
Blazer 200 gr HP ammunition as well as
Gold Dots. There are other factory .44 Spl. HP loads as well, plus you could always carry a factory 240-246 LSWC if you're worried about being able to penetrate thick winter clothing. You can also shoot .44 Russian ammo out of a .44 Spl. if you are possessed with the desire to do so.
As far as .357 Magnum, it's quite sufficient for the job at hand, too. It is easier to find factory HP ammo if you only shop at Wal-Mart, plus you can shoot .38 Spl ammo out of it if you want. Muzzle blast/flash out of a .357 Mag starts to get excessive as the barrel gets shorter, and this is especially true with defensive ammo.
I wouldn't feel under-armed with either, but I think I'd carry the .357 Magnum myself just because I'd probably carry a 2 3/4" Speed or Security-Six.