Is HD-SDI Best System For Surveillance?

No. The short answer is no, SDI is one of the worst overall.

Basically, it is higher price but with less product options than TVI or CVI.

We have a post that compares all of these here - HD Analog vs IP Tutorial

Let us know if we can answer any more questions.

No, with one small footnote. In case you are debating this with someone who is pushing SDI, they may be saying SDI has the best quality image.

Theorectically this has a grain of truth to it, since SDI is an uncompressed digital representation of the signal, unlike the others you mention, which are analog and uncompressed, or unlike IP which is digital and compressed.

But in practice, this most minor of advantages is easily outweighed by the many disadvantages which John alludes.

HD-SDI is NOT a good application for security video. It was designed for high quality studio, movies, and television work - see SMPTE (Society of Motion Picture and Television Engineers) 292M standard. For 'local' production, latency, processing, and consumption it is the superior option. The key word is 'local'. The high quality includes a data rate of 1.485 Gbps (yes: 1.485 X 10**9 bits per second and even for 2.970 Gbps for 3G-SDI). If you want to transmit and store, the video needs to be compressed with H.264, JPEG2000 (advance MJPEG), or similar. Thus it isn't a good nor cost effective option for security video. I would not however call it bad.