I have NOT tried a Blackhawk CQC holster, but I can certainly comment on IWB vs OWB for big guys (6 ft 350#) and many holsters specifically as I have tried many and used to sell top quality leather holsters on the net.
First of all, OWB is always going to be more comfortable than IWB. IWB is usually going to be more concealable, but I don't think I print with either. Nobody has ever told me that I was showing, and my friends that know I carry sometimes ask me if I am, when I am

. I have a problem with my pants slipping down and although suspenders are the answer I don't always like to wear them. A wider spread profile holster like a Bulman Dual Loop, or a Del Fatti ISP-LP, or a Sparks Watch Six works for me, YMMV. As I said, OWB is more comfortable and my all time favorite OWB is an Alessi CQC-S which I wear right at 3:00. I think it's safe to say that it's the most copied OWB holster in the world and that almost all concealment holster makers have their version. Nuff said ! Sadly, Lou Alessi passed away and while the company lives on you may wait quite a while for one. The other close clones like a Bulman QRH are a very long wait too. A quick and great solution is a Minotaur Gladiator, available from comp-tac.com, with leather next to the body and a kydex scabbard. The loops are very well spread and the design holds your weapon close to the body. You can get one in about two weeks last I knew and they are amazingly comfortable. A thinner gun like a 1911 or a Kahr or a H&K P7M8 will disappear under a t-shirt or a polo.
I suspect that you are considering a holster based on price alone. Like I said, I have no experience with Blackhawk, but I don't think a concealment holster is a place to economize. Good luck...Tom