I'm not sure why you'd come to such a conclusion: on the cpu side, you've access to the same amount of CPU horse power and highly optimized cross-platform apps (say, Adobe Photoshop) can use the exact same optimizations on either OS, because of the way it is programmed. In the GPU department, you're correct because Windows drivers of regular graphics cards are optimized for games (i. e. speed over accuracy and consistency). But if you're seriously interested in games, you'd want to boot into Windows anyway.
But other than that, if all things are equal (e. g. if you boot a Mac into Windows and OS X), it'll give you very similar performance.
There are some things which do not exist as such on the other platform, e. g. there is no direct Windows equivalent of Fusion Drive (you can use a small amount of flash to boost boot up times, but that doesn't give you nearly the same performance or the same advantages as Fusion Drive). Moreover, the newest line-up of Macs already use PCIe SSDs which have 50+ % more throughput than the fastest SATA SSDs on the market (which are limited by the max throughput of the SATA interface).
Moreover, battery life under OS X will be significantly longer than under Windows.
I'm not quite sure you understand what Unix actually is, »Unix«*doesn't gather dust and starts creaking. Apart from the legal definition of Unix (by which Linux is not Unix), they follow the same design philosophy. In that regard, Windows is not really better or worse (the NT kernel was started 20 years ago in 1993). But these OSes have little to do with what they were 20 years ago. And both need to straddle an amazing range of devices, from 12+ core Xeon machines to puny a single Cortex A8 core you find in an iPhone 4 or similar (the NT kernel is also at the heart of Windows Phone 8).
1) OSX is based on the Berkeley Distribution which is a UNIX variant not Linux.
2) I will never defend Micro$haft OS as it is, even with rebuild - bloatware. However, UNIX is an older system and even with changes, it remains steadfast in keeping some rather outdated and antiquated features including a command line that is based on limits of 2nd generation use of ascii.
3) We have to be careful (myself included) in comparing Apple to non-Apple as it can get, no pun included - an apples and oranges comparision.
Non Apple PCs have had PCI-xxx SSD available already. Cost is what drives them out of the hands of the typical user. If we consider non-Apple PCs as boxes, they are (other than the present Mac Pro) easy to swap out, add too and upgrade unlike an iMac or Mac Mini (beyond hard drive and rather limited RAM). Apple's model is to have a fully self contained unit that people buy, turn on and use. Much of the decisions are made for the Apple user base ahead of time.
Photoshop - time and time again, under tests the Windows based system with similar or same basic hardware edges out the Mac. This is no secret but then again it is no secret that 95 percent of the time, it makes on difference with respect to the end user. As far as hardware acceleration, Windows again does better. In fact, some Mac/Photoshop top dogs suggest Photoshop runs better without using hardware acceleration with some video cards that are common to Mac and state it only helps for a couple of activities/filters and otherwise can slow down Photoshop. Again, given a good robust Apple, properly matched to Photoshop needs, most people are extremely happy with this combo (myself included).
OS cost - goes to Mac
Computer cost - depending on how you look at it, I'll sit in the camp that non-Apple PCs are, independent of OS a better buy usually or more bang for the buck.
Upgrade-ability - other than the present Mac Pro, usually goes to the "box" PC. From drives, various cards including graphics, audio and esoteric port oriented cards.
Port connectivity - on pure speed the MAC wins hands down with both USB3 and TB
Typical port usage - tie, as most people wont be buying (for now) TB and that means USB3 is available for both MAC and non-Mac PCs.
We can go on and on about this and either agree or disagree. Bottom line is if Apple's products work for you and you prefer it and can afford it, by all means remain in the Apple camp.
I have built so many PCs over the years ranging back to early DOS days and enjoy creating a computer - built to spec so to speak but gladly happy emptying my wallet into Mac products and will continue to do so. I do have things about OSX that I really find annoying but not enough to dissuade me. My next purchase will be either the next generation of Mac Mini or the new Mac (mini) Pro. The latest changes to the Mac line up, which includes much of what you mentioned, makes the Macs relevant in today's competitive market as far as the hardware is concerned.
Cheers and hopefully you, like myself, consider this just a casual exchange and I do appreciate your comments.