I suspected that this cable would just stop my Panasonic DVD/universal player from having the occsional sulk/wobbly via Scart with my new LCD telly. However, once set up the quality improvement over RGB Scart was a pleasant surprise - not revoloutionary (as in black and white to colour), but evolutionary, as in going from DVD to HD. OK so it's not actually HD quality, but as my budget 26" HD telly is not 1920x1080 (i.e. full HD) I can tell little difference.
If your telly and DVD player (or set-top box) has component outputs and no HDMI connector, then this method of connecting is worth doing. Remember that this cable is the vidual signals only, and you'll need a two-phono-to-phono lead to handle the stereo audio - my Panny is connected to my 5.1 surround speakers by analogue phono leads so I don't need the stereo audio pair, but for a device-to-telly you'll need the stereo pair for audio.