I had a 2006 MBP that I loathed, shitty fragile hardware, every piece of software I used on it was somehow inferior to what I'd been using in Windows-land, probably one of the worst $3000 consumer electronics purchases I've ever made. I went Windows more or less since then and was pretty happy with whatever I had since then.

A few months ago my work got me a MBPr (much to my chagrin at the time) running Mountain Lion, and you know what? It ain't bad. My boss insisted that I give it a shot for a few months and if I still didn't like it they'd call up dell and get me whatever I wanted there.

Most of the initial problems I patiently chalked up to re-familiarizing myself with the OS, especially in the ways it's subtly changed since 2006.

Off the top of my head

The good:
I don't think I can get a better system for spinning up 2 or 3 simultaneous VMs eating 3-4 gig of RAM a piece and having the whole system still run blindingly fast.

CMD+Space to find stuff works pretty brilliantly most of the time.

Searching for help is usually more helpful than I was expecting. I've almost always gotten help from the OS in clever and useful ways. The control panel search for example, is far superior to Windows.

When SSDs were first introduced I was skeptical, expensive and the space seemed far to small to be productive. I still wish I had about a TB of space like my old Dell had, but I'm just a bit more judicious about what I jam on there. SSDs were definitely the right way to go. I feel like I'm working on a $300,000 piece of server equipment.

The high DPI, bright screen is really nice to look at all day. I don't really think non-retina art looks like shit the way lots of pundits make it out to be, and overall looking at stuff is great.

There's some cool OS X only stuff out there where there's not really a good Windows variant. My favorite has to be Cathode. But there's lots of interesting looking writing and creativity software as well.

The trackpad really is that good. The barely functional PoS on my 2006 MBP had me tricked that any old trackpad on any old laptop was more or less the same. But I actually prefer to use the trackpad on my MBPr to a mouse. It's really more a size than a texture thing, but there's some slick software backing it up, movements are precise and the cursor goes more or less where I want it. Gestures are cool even if I only use 3 or 4 of them and they function much better than their Windows equivalents. I really do like two finger scrolling much better.

Multiple desktops work really well. I keep work stuff on one desktop, and personal/break stuff on another and fine transitioning really easy and helpful in compartmentalizing my day.

Notifications are better than in Windows. I'm actually usually pleased to receive a notification in OS X, whereas in Windows it seems like such an annoyance. Icons in the toolbar jumping up and down is also helpful. I don't autohide or zoom my toolbar, but I like it in general.

The physical hardware is awesome. It slips away into my backback so nicely I have to double check that it's actually in there.

A decent number of connectors for peripherals.

It does relatively smart things when connecting up extra monitors.

The keyboard is quiet, but really comfortable to type on.

The bad:
I spend 90% of my time in terminal window or a web browser, things for which most of the good things above are entirely superfluous. Plus Chrome has some annoying hard edges that make it work worse in OS X than in Windows. I could literally get along just fine with my Android tablet and a keyboard for what I spend almost all day doing.

Window management is in general, worse than in Windows. Complaints include: tiny, over precise click targets, buttons on the top of windows which have unpredictable behavior, closing all open windows doesn't close the app (leaving zombie apps open and pissing me off 6 or 7 times a day), the menu bar is detached from the app window and with the poor maximization behavior makes knowing what application I'm in a confusing mess that bits me at least 3 times a day, unbelievably small and frigidity scroll bar target. Coming from windows, I never really got why Fitt's law was such a big deal to Mac users, now banging around this clumsy environment I finally get it. It's almost impossible to accurately and easily move things about your workspace. Better to just open the app and let it be and then get to work and just deal with whatever the window is doing.

Mouses suck in OS X. After some serious consideration I think it's that the OS has been subtly optimized for the trackpad. But it's subtly an inferior experience to mousing about in Windows (while the inverse is also true, Trackpads are inferior in Windows). Acceleration curve is never quite right, mouse wheels track in less predictable ways, and for legacy reasons right mouse button is very much an afterthought.

I find I'm often surprised at what isn't in the OS and results in getting nickle and dimed by the ecosystem to "complete the OS". Really no basic paint program?

Why, oh why, do I have to play finger twister all day with keyboard shortcuts? Really? Some of this shit is unbelievable. CMD+CTRL+SHIFT+4, Space, click and yay! I've taken a screenshot of a window! You have got to be kidding me. Far far too much is buried in the OS, and undiscoverable, behind layers of program altering button combinations...it's so bad that even lists of common shortcuts don't work half the time!

Office on windows is a hair better. There's lots of nice touches in Office, so it's not punishment to use it. But the Ribbon/menus just work better in Windows...no surprise.

It's more unstable that Windows (at least since XP). Sorry, it just is. I have to reboot my Mac at least twice a week and all I really do on it is use Chrome, terminal, ssh and run a few VMs. My creaky 5 year old home machine running 7 hasn't been rebooted in a couple months and generally doesn't flake out. I've heard this is a recent Mountain Lionish issue from the rest of the folks in my shop, but still.

The ugly:
Finder is an absolute abortion of a file management tool. I could go on for pages and pages, but virtually every single thing in Finder is done wrong. From the default behavior for Enter to just simply knowing where the fuck you are in the file system. Explorer is light years better. I feel like I'm constantly stuck in an emulator showing me the worst of early 1990s file management tools from an Amiga.

Multi-monitor support is just...broken. It feels like such an afterthought, and other than turning things on and moving windows around smartly, almost every other activity after that feels subtly broken. It's hard to explain, but the best and most notable example is Mountain lions full-screen mode...which works brilliantly on the laptop by itself, but fails entirely in multi-monitor mode. This something windows hasn't had a problem with for something nearing 20 years. It's not that hard. It's also in multi-monitor mode that the failure of ideas that the menubar is starts to become rapidly apparent. Having to pad on my trackpad across two monitors to click a menu, then pad all they way back to where I was is a distracting waste of my time.

There's an uncountable number of ways to switch between applications and programs, yet none of them are as simple or reliable as windows. cmd-tab switches programs, but I spend half my day hunting around for the window I thought I had open, only for it to be minimized or behind another window. Moving to the toolbar means taking my hands off the keyboard, and on and on and on. CMD+` doesn't work in every application reliably.

I have yet to conceive of even the slightest use for the Dashboard.

I have other, smaller praises and gripes, but none of them rise to the level of daily notice like the above do. But overall, I feel generally happy in my computing experience during my work day. I don't feel like I'm in a penalty box when I fire up my work laptop and being able to my work without too much fuss is decent.

Some of the nice things in the OS make me feel like windows is a bit clunky in appearance when I go back to my home machine. OS X overall definitely feels smoother in most respects. Even simple things, like a built in SSH client are huge.

But once I adjust back to Windows, and realize I can stop fighting with basic file management issues and other OS X complaints I have, I find I still personally prefer Windows for my personal use. Most of the stuff I want to do in my off-time is Windows only (or the Windows version is simply better), and so that's that. I just don't see me buying a Mac for personal use as none of the things that are offered by the software ecosystem appeal to me in a holistic way. There are spotlight of brilliance that's for sure, but on the whole I still think Windows offers a better, more diversified and more vibrant ecosystem overall.