It is the Fastest Microsoft OS to Boot (even faster than dos).
It is the more stable
It is the more modern (all drivers, software, emulator that are coming now, works for it)
It is very customizable and optimizable.
May be it take more space on hard drive than 2000 , but you can always remove what you don't need.
2000 is very good too, but why took 2000 , if you can put XP . It is almost the same core and more modern.
In my cab, i have a amd athlon XP 2000+ , 256mega de ram , hd 40giga , ArcadeVGA. It boots directly on the Front End in 11 seconds under XP.
On the same machine ,under dos with Advmenu as frontend , it boots in 15s . (and i have no CD Drive access, if i put the cd driver it tooks 3 seconds more).