The 239 is my favorite 9mm that isn't a CZ, and for discreet 9mm CCW is hard to beat. Utterly reliable, very accurate for a short barrel, and yet substantial enough to soak up the recoil (if any
) from the 9mm +P+ loads. I carried one when I was limited to 9mm by my employer, and carried it in either a KyTac Braveheart or FIST-Inc. Adjustable IWB. Both holsters were great buys for the money, and I would throw the Fobus in the crapper and get one of those, if I didn't have the money to buy a Milt Sparks Versa-Max II.
Keep in mind that holsters that are well-made and well-designed may just not WORK for YOU. Different people have different builds, and carry weight differently. I have a box of holsters that are great holsters, but just didn't work for me. Most pistoleros do, as well.
Don't worry if the P239 is or is not a popular piece. It's a GREAT one. If I was stuck carrying a 9mm for CCW, it would probably be that one. Not that I don't love CZs!