I bought this card for a media centre I was building not but a few months ago. I was surprised at the size when I received the box. It is almost half the size of an ATI Radeon HD 4870. It is a single slot solution featuring standard VGA, DVI and TV out.
Whats it for? This card is perfect for computers that require little graphics processing for video output (playback) and therefore media centres (especially due to its small size).
Why is it good for the purpose? It has a very low sonic and thermal output. Even after using it for eight hours it manages to climb to 70 degrees. It also manages to run AERO on Windows Vista and Windows 7 without any problem. It scores a 4.1 on the Windows Experience Index which compares to a 5.9 achieved by the 5770/5850 series of Radeons.
As mentioned it is very small in size and therefore fits in Micro ATX and media centre format casing. There is no extra power source required as it draws power from the motherboard through the PCI-e.
What it is not for? Its not for playing high spec games such as Call of Duty Modern Warfare 2 or Battlefield Bad Company 2. It can however handle a session of Half Life 2 but don't expect blistering performance. This card isn't designed for blistering performance.
Media playback? The card for its low price and size can actually play 1080p Full HD videos which is why this is such a good choice for making media centres with. Not many other cards can boast DX 10.1 and 1080p support at around £30: no Nvidia card is available at this price range that can boast what the Radeon HD 4550 can.
Office use? Of course if your computer is just for office use and general browsing then you may not want DX 10.1 or FullHD, but don't forget that if you do watch clips and have a large monitor this card will be a better investment than those at a lower price range of around £20.
Final Word? Good little nimble card ideal for media playback as it supports Full HD and can handle most 2D games and some 3D games. At around £30 its great for media centres or office use.