I carry a Sig Sauer P238, rainbow with an extended magazine because I generally must carry small to properly conceal it in my pocket. I use the Sig kydex holster that came with it and it works quite well. When I am dressed with a sweater, jacket, or an un-tucked shirt, this system also works well OWB. For those with long arms like me, I recommend cross draw carry.
I recently purchased a Alien Gear Cloak Tuck 3.0 Holster (also shown) but I just got it. So far this holster seems to work well too.