I think the Blackhawk Serpa holster is an outstanding design for a duty holster, but it’s not a very good design for CCW.   I remember all of the bashing that use to go on about Glocks vs 1911 handguns for CCW and the arguments  usually came down to people being against manual safeties.   I think there is something to be said for not having a manual safety on a CCW gun and there is a difference between that and having one on a hunting rifle, but it does not make sense to argue that a 1911 is bad for CCW and then tote your Glock 19 around in a Level 2 holster.    You have to weigh and balance the advantages and disadvantages of a firearm and how you would want to deploy it.

The Blackhawk Serpa works well as a duty holster and under a vest or a jacket it can work, but I never liked the idea of having to clean a layer of clothing, find the gun release and draw the firearm.   I stopped carry a 1911 after having too many times of missing the thumb safety.   The more you layer your clothing, the more of a risk you are going to run into a problem.  Blackhawk holsters do come in an IWB design that are of a nylon design and better suited for CCW.   I have found there are some advantages of a simple nylon holster for a Kydex or leather.