GTA4 Downloadable content

I was just reading in game informer how XBox 360 gets this exclusive DLC for GTA4.
it is changing how DLC will be done.
I guess its pretty much a whole game in itself offering 20 hours of gameplay.
I think this is really cool and a great exclusive for 360 fans and GTA fans alike.
The content will run about $15-$20 but seems well worth it to me, considering the graphics are even more improved and the story continues flawlessly.