im a massive C&C fan, and having played both the PC and 360 versions, i have to say that the PC version is better.
the game as a whole is great. the story is involving, its great to have an extra new army in it (the Scrin), and the game is just really addictive! it combines pretty much all the best bits from previous C&C games, and adds to it many new and great things as well, from the support powers to the ability to upgrade units and garrison buildings, which all adds more depth to the C&C universe.
the bad side, is that the controls can be frustratingly fiddly compared to the PC, where you obviously have a mouse and a keyboard instead. it sounds a small gripe, but in actual fact it makes a fair difference on harder difficulty settings. online, i guess everyone else is in the same boat, so you wont be disadvantaged per se.
its also annoying that the Intel pages have been removed - on the PC version you would pick up bits of Intel if you achieved certain objectives which gave you in depth information about characters, units and the story generally! it made the game more interesting and gave the player more background to enjoy. again, its a small gripe, but its something i miss.
overall, an excellent addition to the series. its difficult to play on an XBox pad, but you get use to it (its still not ideal though). i guess thats my only real complaint. excellent game. well worth getting if you're a strategy fan.