I use Backhawk CQC holsters for outside the waistband carry, they aren't super concealable, but are very comfortable and have a retention lock.
For inner waist band carry I use a Galco, very good holster. IWB is the only way to go for concealment, normally not quite as comfortable though.
Congrats on the purchase, I have a Gen3 19 and love it.
Just passing through...