I really like the Safariland 6377 for Sig P220R. Note that there are different models for the railed and non-railed versions of the P220. It's a belt holster that has an active retention lock. It's comparable to the Blackhawk Serpa, but it's (IMO) better because the release button is activated by the thumb rather than the trigger finger. So there's arguably a smaller chance of having a negligent discharge, and I find after a little practice, drawing is very smooth and just as fast as an open top holster with no retention.
The lock seems very secure. I tried pulling very hard on the grip of the gun but I couldn't get it to come out, or anything to break. A notable feature is that the inside of the holster is suede lined to ease wear on the gun.
The holster sits comfortably on the belt and is fairly low profile as far as outside the waistband holsters go. It
would conceal well with a jacket or vest, but not with anything less. Note: the model 6378 is the same thing but as a paddle holster rather than a belt holster. The paddle would make it stick out a little more, but may be more comfortable and presumably allows for easy on/off(I haven't actually seen it but generally paddle holsters have that option.
Thumbs up for a comfortable and secure range or open carry holster.