Overall I have found that the Radeon X300 works fairly well to boost your computer's graphics capabilities, and it definitely is an improvement over integrated or embedded graphics that most computers come with, and has helped my computer run graphics intensive games more smoothly. Compared to other graphics cards from the other main brands, it is at the budget end, and I would recommend if you want to use your computer for any seriously graphics intensive programs to invest in some more MB, as 128 is fairly low compared to many others on the market, and of this it borrows quite a bit from your system's RAM. I have read that it does not support Vista's DirectX 10 standard, but I do not use Vista so this has not been an issue for me.
It also advertises that it provides another VGA connection so you can run two monitors from your desktop, as it is capable of outputting signals in a form compatible with TV's. This works fairly well, although I've never found any real use for it. Overall, it is recommended for casual gamers, but those looking for more should really invest in one with more memory that will keep up with new programs.