Can't say I'm surprised at the month delay. Microsoft want to ensure this game hits the competition in one quick blow. For that it needs to be the best it can be.
For those who don't know what Forza Motorsport is - it is the racing simulator. Some might compare it to Gran Turismo 4. But that's probably not a fair comparison, as it totally destroys Gran Turismo 4 - it's probably best to compare it to say Gran Turismo 9, of course if the series survives that long, actually you know what - I don't think PD could deliver all of this even if they took another 5 versions.
A run down on the features that destroy Gran Turismo 4:
More realistic gameplay.
More realistic physics.
Full damage modeling.
Totally customizable cars.
Totally tunable cars.
Online garage where you can sell your cars online!