It is impossible to discuss anything that has to do with Microsoft because it has become politics. I notice however, that no one is claiming that Vista is unstable in any way. So we are back to

1. Long start uptime and
2. Being a memory hog.

So why don't show by an example? I have a fairly new computer bought this year. An Intel Core 2 Quad (4 X 2.33 MHz) with 4 MB memory. The price was $1350 (without monitor and peripherals). Hardly high end, rather normal.

It has 156 programs installed, large and small. All was backed up on a Acronis backup, it took less than  one hour to get started, unpack, restoring the image file and download drivers.

The start-up time is 1 min 25 sec until I can see my desktop and can begin to use the computer. Another min for the computer to start all services and go to idle status. (The shut down time BTW, is only 10-15 sec). It is starting from sleep mode in 4-5 sec.

And memory? The fact is that no matter how much memory you have, Vista is using it more effectively, because the graphic card take much of the load unlike XP.

Regards from
Mythbuster

(Remember, Windows 7 = Vista + cosmetica)