I wouldn't totally agree with Soundy, because he's being a bit unfair about the whole situation.
First of all HD cctv sistems can offer simplicity IP sistems lacks. Just plug it in that's it, no networking knowlage needed, no protocol compatibility needed for different developer HD cctv cams and HD DVR.
Soundy was true, SDI has limitations 2 MP, but since this technology is rather new, there's a posibility to have even higher resolution in the future. For example, not to long ago, 3G SDI interface was developed, enabling to 1.485 Gbps.
Most of installers will agree that too much MP is not an awnser. And the optimum is about 2-3 MP, because IP cameras with have 5 MP or more, are absolutly blind at night and have a low frame rate per second.
But the main advantage of this sistem is that praticaly has no latency, could be a solution in some precision needed places, like shops, gas stations, banks. Even more, HD cctv can have 60 f/s, that make it even better for this situation.
So in conclusion, I'd like to say that HD cctv can find its place in a market for sure.