Logic X performs fine on Mac Pro’s from 2009 on. The reason for that is that Apple did not refresh their Mac Pro lineup significantly for about 5 years.
I’m sick of hearing about how much better Cubase/Nuendo are on Windows. Even if it performs better, I would not want to deal with the constant stream of Windows updates, the absolute necessity to maintain anti-virus, anti-spyware, and anti-malware software, and the hideous Windows 8.x interface. All of which I, unfortunately, have a lot of experience with, because it’s part of my job to keep my Windows users running - none of whom are musicians BTW. All of the many composers I work with use Macs.
I love Nuendo. It is stable and powerful - on my Mac Pro. However, it is 6 times as expensive as Logic X, and doesn’t include as much additional content. And it is 3 times as expensive as Cubase. Does Nuendo really offer 3 times more features than Cubase? Steinberg should combine them into one product, IMAO.
The price is not an issue for pro’s making a living at music - they will buy what they want and need, and can justify the expense. But there’s no doubt that this price competition will reshape the market. In a good or bad way? I don’t know.