I want to deviate with Underhand on a few counts. Ill run through my playgroup armies and explain my view.
My friend has been playing his deamon army against me, with some success, and i have learned that the Hellhound is superior to the Banewolf in this case. Deamons will generally use 1 of 2 kinds of troops. Nurgle or Khorne. Khorne will get up to you and cut you down, badly, and against these men both are effective. But it is against Nurgle that the Hellhound shines. The strat is often that with Nurgle you Go to Ground on an objective. As such, they get a nice Cover Save and the FNP save. I have found the easy wound is not as useful as the range. Often the deamon player will plant his nurgle guys, and bait you. The ability to deny cover save, and remain 12-18 inches away is invalueable. And trust me, you don't want to drive your precious FA tank ANYWHERE remotely close to a soul grinder or Bloodthirster. Or any greater deamon for that matter, or deamon prince, or AT Tzeentch units. basically there are ALOT of things you don't want to be near.
Against SM, definitely the Banewolf, the AP stat makes it obvious.
Nids, definitely the Hellhound
Necrons, look at SM
Against IG, i would suggest the hellhound, because if they are mechinized, the extra range allows you to pop their Chimera, then waste the occupants, all while staying out of melta range. If they arent mechanized, then the inferno cannon will kill better than the banewolf anyway. I don't see how a BW would be good, unless they are bringing GK.
DE, Def the Hellhound, for the same reasons it is better against guard. Plus, in a pinch the Hellhound can hurt DE and IG transports, which the banewolf cannot. I have ONCE gotten two wrecks with an Inferno cannon on raiders in the same shot.
Basically, i rate it based on Save. 3+=BW, 4+=Hellhound. Deamons are Invuls, so it doesnt matter too much, hence why i value the range over the easy to wound-ness of the BW, unless you are trying to use your BW to hunt his MEQ Greater deamons like his Bloodthirster, which ill tell you now, is a bad idea.
So that is my view, hope it helps.