This is not intended as a full review - just my experience to help buyers with similar requirements to mine.
The cable is not fully shielded and I experienced slight fuzziness on 1024x768 resolution. On resolutions above this (esp. 1280x1024) quality degraded sufficiently to be unusable (serious ghosting issues) rendering the cable somewhat useless considering that the reason for getting away from the TV was to avoid low resolutions.
The cable is 2 foot shorter than the official cable (~1.78m) so if you purchase this cable ensure that your Xbox 360 is positioned very close to your screen.
Finally, the distance between the audio jacks and the VGA connector is very short (from the split to the end of each is ~53cm so total distance between the two is 106cm) [although this is also an issue with the official cable].
Overall I found the cable to only be suitable for people who want their monitor at resolutions 800x600 or less with their 360 and amplifier very close by. For others the official cable may be the path to go (even though, at ~£15 when shopping online, it remains a rip off).
Edit: On a *different* item listing showing an identical product Sumnique state that "Sumnique Limited Are The Manufacturers And Sole Distributors of Sumnique Products, Please Be Aware of Cheap Copy of Sumnique Products. Please Do Not Leave Your "Customer Review" On Sumnique Products If You Did Not Order The Genuine Product From Sumnique Limited". That said, the line is not on *this* product description and I cannot say if a "real" Sumnique one is any better, so be careful with your purchase and be prepared to send it back if it is not right.