Springfield Armory XDS.45
About the size of a hand, 5+1
Punishing little bastard to shoot at the range, but gets the job done. Might recommend the new longer barrel version over the original.
Make sure if it's used that it has the extra pin in the rear from going back to Springfield for the recall. They were fixing a possible slam-fire problem that could ruin your day when loading it, so ask or look at it for the additional pin.
Trigger safety wasn't always resetting, and if the grip safety was also depressed, as in, when racking a round into the chamber, the striker wasn't held back -- and could, in theory anyway, go forward with enough force to light off the primer and have an unintentional loud noise.
Depending on your feelings about liability of modifications on a defensive pistol, the Powder River Precision trigger kit makes it a better shooter, IMHO. But I haven't modified mine.
If you get one don't be ginger with it. It likes it rough. Grip it and rip it to rack it and get as high and as solid a grip as you can on it. It'll run great. Don't be shy. Most problems I see reported are folks being light handed with it instead of whaling on it.
If you're at all recoil sensitive, go with the 9mm version.
Keep in mind that muzzle velocity is down at least 150'/sec with the 3.3" barrel from the manufactured spec for any ammo. Speer and a couple of others make special "short barrel" versions of their ammo.