People who have gotten OS X working on Atom-powered netbooks say it's really slow.
Not true.
But I am a bit bemused as to why Atom would go into a desktop, other than a media centre sort of machine. I was actually thinking of an EEE Box to go under the tv, but I might hang off to see what pans out on this.
Out of interest this is where the Atom 330 stands in processor benchmarks (From here)
Where are you going? Get back to fundamentals please