Sounds to me like this is just a matter of what you're used to. From my experience, OS X's UI is the last thing anyone would want if they weren't used to it. The window management is pretty damn horrible. OTOH, Linux has a variety of window managers with many innovative paradigms.
> I like Lenovo's build quality and aesthetic, for example, but their laptops are universally underspecced for what I want (if your only GPU is Intel, you are not getting my money) and I can't get a Retina display, which I now consider mandatory, anywhere else.
I don't know what you're doing with your machine that makes Lenovo machines underspecced, but for web and Android development, the ThinkPad X1 Carbon fits the bill. I wrote about it here: http://news.ycombinator.com/item?id=4848375
If you want discrete graphics, that is available in other models, such as the T series, IIRC. However, for anything other than gaming or video editing, integrated graphics really is enough. I personally prefer not having discrete graphics, as it keeps me from playing games.
The only thing missing is retina support, but you have the advantage of a lighter and thinner laptop than the MBP. It's no different from the MBA in that respect, with the added advantage of a 14" screen in the same body size as the 13" Air.