I own a 4" SP101 and a Henry Big Boy brass rifle. Here are my thoughts in no particular order:
1. Forget finding loaded ammo on the shelf, at least where I live in Central IL. If you buy a gun, just take five more minutes and buy some brass and bullets.
2. As far as I've been able to find, the only jacketed bullets available are XTPs in 85 and 100gr. if you can find them.
3. Personally, I think .327 is an even better rifle cartridge than a handgun cartridge. Load it soft for smaller game like raccoons or coyotes, up to full tilt for deer if legal where you live (for shot distances within reason and good placement). I used my Henry to shoot a pistol cartridge silhoutte match once, and it was pure fun! The rifle pointed and balanced well, and no recoil to speak of.
4. If I did things over I would buy a 3" revolver for CCW and a 6"GP100. The 4" is a little long for CCW, and a little light for repeated shooting full bore loads. If you wanted a general purpose gun to carry in a hip holster, it would do nicely.
All just my personal opinions, of course.