When you say many, do you mean consumers? Or enthusiasts? Or IT people?
If you are talking corporate environment, OSX offers everything that a Linux box will do, and more. And I can tell you, its a load easier to manage and setup. And from a performance perspective, the G5 isnt faster, but its definitely close, and certainly fast enough. The only thing remaining is what Apple's support is like, and this is where companies like Sun shine. If Apple were to put that last piece into place, they have a very compelling product.
If I were an IT person, its worth a look. OSX is miles easier to run than Solaris (in my opinion).
Benchmarks are just that, benchmarks. They are truly one dimensional. Whats the point in running an Opteron box if it costs you an extra $10/hour to run AC and power for it? This is not even taking into consideration the overhead of having to pay someone more money to manage it (come on, Linux admins make more).
Like I said, close enough that it hurts AMD, bad.
