"Empirical measurement" in this context can be a hard thing to get. Sure, some things are clear: for a Mac of a given price, you can get a nonMac with more processing power than the Mac. But then there are things like battery life and weight, where - to my knowledge - Macs tend to do better. I'm not convinced that the "better hardware for price" argument is all way one traffic, to be honest - but I might be wrong as it's been about six months since I've looked around at nonMac notebooks (I was considering buying one then, just for the prospect of saving money, but I didn't really find anything which made me feel like the saving would be worth it.) And then there's the design and the OS, and here's where "empirical measurement" becomes a tricky issue, because (i) whether the aesthetics are appealing and whether the design is "intuitive" is to a large extent subjective, and (ii) the weight one puts on these issues in comparison with the other things (like processing power, etc.) is also largely just a matter of one's preferences.
eh, there's no magical super-material in macbooks that makes them weigh less than Windows laptops, so they do weigh the same (different companies use different materials, but I find Asus, Toshiba and some MSI laptops to generally be light, and HPs to generally be heavy). Battery life depends on many things: Macbooks all use the same amount of cells, which isn't true for Windows laptops (once again: it's a scale thing). And, of course, what you have running will effect battery life. Like above, I find Asus and MSIs to have very good battery life, comparable to a Macbook Pro given the same screen size. Laptops comparable to the Macbook Air (which I wouldn't recommend right now due to aforementioned lack of TRIM support) in terms of battery life can also be found.
The boot time between Windows 7 and OS X is also comparable given same hardware and given same install state (as in: one is not running a bunch of crap and the other isn't)
The differences are completely fashion oriented as far as hardware is concerned between the two. Software is another matter. There are more variables to consider, and the pros both have on this layer can also be argued as cons in a different light. From a strictly functional standpoint, both are on pretty much the same footing here. Both excelling in one niche while falling short of the other in a different one, though even their excels and shortcomings are by a fraction's distance.
As for intuitive design: it is by far mostly which you grew up with first. Everything has a learning curve, and once again, each has their own advantages in ease here too, handling things in different ways.
It's a shame that most Mac OS X users are allergic to the terminal, though, they have such a powerful one now.
Maybe in the end it is just "because I like it". But I'm not sure why that's such a bad reason. Should I not be guided by my preferences when purchasing something? Or perhaps the thought is that this somehow suggests that I've got irrational preferences; but I'm not sure how one would make that argument.
Neither is true, however, when dealing with asserting something based on preferences, you should say "For me, it may be, but not necessarily for you, as it is my preference" or something along those lines. Recommendations without reasoning are not completely worthless, but not particularly valuable. That is not to say it isn't a factor, but that it shouldn't be a driving factor.