I just bought a MacBook Air last week, after a 2 year break without a Mac laptop. I had been using Lion and Mountain Lion on a Mac Mini, but the last week or so have been a revelation for me. Crazy battery life (about 9 hours of normal programming), full screen apps with swiping to switch between them, fast fast fast at everyday operations thanks to the SSD, the whole thing is at the same time a major turn towards iDevice-ification, and a giant leap forward in usability for laptops.
I wonder how many people worrying about iOS-ification are:
a) running Lion, where the transition was still in mid-course, or
b) using a desktop, where the design decisions aren't so obviously right (my Mac Mini for example has a huge monitor, hence I'm less inclined to use full-screen apps)
In case a), there were definite weakness in Lion. Full-screen apps hadn't yet made their near-global appearance, and Spaces was ... weird. These problems have been shaken out in Mountain Lion. For b) it seems to me that OSX has been optimised for the laptop environment, where screen real-estate is limited. If you aren't using full-screen as your standard app config, you're missing out on some of what makes Mountain Lion a great experience).
When I compare all of this to the laptop I use at work, a Dell running Fedora, there is no comparison. My Mac is a far, far better development machine (well, aside from the fact that brew is weak sauce compared to a full-blown yum, but then this is not news). It's not a question of there being pros and cons on each side, my Mac is simply better for pretty much any metric I care to imagine.
Which is not to say that some people may not have genuine grievances with the current Mac platform. I just wanted to add my own personal experience - going from being mildly disappointed by Lion to completely wowed by Mountain Lion.