Yes this came out in the Save XP thread currently running in SC.
The most obvious point to make is that MS and timescales are not good bed partners, so many times deadlines have been missed. I think it unlikely from past experience that a late 2009 date is achievable. I realise the boss of the 7 team has been responsible for some of the more timely MS offerings but an Office suite is quite different in complexity to an OS.
Vista was test driven like no other OS and many including me find it to be both fast and stable. There are issues for some gamers but much that has been laid at the OS door in fact relates to many other things including dare I say the people using it.
On the point however I agree with you, let it take another year if it takes that time to put out a well tested product.