The downsides of moving to OSX (say: OS Ten) and Macs are, amongst many, these:

1. -Pay for software AGAIN: If you have Office for Windows, you can have it for Mac too. But it won’t be free. Same goes for practically all commercial software that has PC and Mac versions. Bummer, dude. (Not that I care all that much, I’ve switched to Open Office years ago.) Update: several games, notably on the Steam platform, offer both Mac and Windows version for one fee, presumably because they’re tied into a user account anyway so you can’t play on more than one platform at a time.
   

2. -Get used to new keys. Mac keyboards have some different keys that are hard to get used to, especially if you’re a shortcut warrior on Windows, like me. You CAN simply plug in a Windows keyboard but then Mac instructions won’t make sense and you can run into (minor) problems. For instance, on the Windows keyboard I have connected to my Mac Mini, I can’t type a capital R. (This is less a problem for me than it is for my brother, Richard.)
   

3. -Also, newer Apple keyboards do not have dedicated function keys, which is inconvenient if you’re running virtual Windows and want to press F5. (You need to do that via a menu or keycombo now.) Also kinda annoying: no delete key. (Use backspace for that.)
   

4. -Expensive accessories. Extra power supply for your macbook? New bluetooth keyboard or mouse? A simple ‘Displayport’ (a Mac-only standard) to VGA cable? All that Mac stuff is very expensive, simply because they can get away with it. And it’s not as if this stuff never ever breaks, it ain’t bulletproof. Shopping around for alternatives is possible, but sometimes you have no choice.
   

5. -No USB 3.0. At the time of writing, no Mac supports USB 3.0. Fortunately, USB 3.0 external harddisks are backward compatible with 2.0 connections on your Mac. Even the cable will fit, even if 3.0 uses a wider connector. (Just use a 2.0 cable and it will fit.) Oh, forget about using USB 3.0 external drives for Time Machine because the machine will refuse to either boot or shut down when connected. Update: recent models have begun to support USB 3.0.
   

6. -Say goodbye to: Pinnacle Studio, Nero, advanced archiving software (Winrar, for instance, is command-line only for OSX), your old webcam (since Macs all have webcams built in, there are hardly any webcams out there with OSX drivers. So if you want to show your kid to your parents, drag him in front of the screen and make him sit still) and quite possibly your old printer or scanner too. Still, you’d have to have a pretty special printer for that to be a dealbreaker. And it will work if you dualboot your machine, anyway.
   

7. -Stupid file management. I’ll be honest, file management on the Mac isn’t quite perfect. Actually, it is piss-poor. Windows users will hate how OSX doesn’t sort folders above files, but just throws them in the list alphabetically. Moving a file requires a key combo (copy/paste works differently, multiple selections are a hassle too) so in the end I decided to get a 3rd party app called TotalFinder, which makes copying a bit easier and sorts folders the way we like it.  (Sadly, TotalFinder is no longer in free beta.) Mac-users respond to this by saying: “Why the hell would you want to sort your files? Just type the first few letters in Spotlight!” Well, yeah, but some people like to keep the place tidy and alphabetized you know. Oh, you creative types...
   Also annoying: once you open a folder, it stays open. Oh, by the way: the 8 dollar app ‘MoveAddict’ creates a cut/paste option and you can get a free trial that works with one file at a time. Also, get the free Easyfinder app, because Spotlight will find your file but it won’t tell you in which damned folder. (Okay, so it will if you hover over it a bit.) I still don’t like OSX file management, but it’s a small price to pay for all the other improvements.
   

8. -Apple is not a nice company. There have been many articles on this subject recently so I won’t go into it too much, but Apple has been the underdog for years and recently they’ve turned around and they became bona fide assholes that made vendor lock in an artform. I’m well aware of that. Also, the more lawyers they hire, the worse their PR gets. On the other hand: I don’t care if the CEO of, to name a random company, Dell, lives or dies either. It’s not as if Microsoft ISN’T evil. Name a big company that IS nice and if you can’t do that, at least name a company that makes quality stuff and has jawdropping presentations like Apple does. Plus, last thing I heard, they weren’t clubbing baby seals yet (although with Foxconn, you never know.)
   

9. -Fixing your own PC is a thing of the past, my friend. With luck, you’ll be able to add some RAM or swap out a harddisk, but gone are the days when you’d take out and replace parts as if you were a transplant doctor in a Mumbai slum. You need very special tools to work on Macs. It is only for the very determined and well-insured. Oh, you will want to save the box, so you can safely ship it to a service centre if you have a problem or want an upgrade! Read more about AppleCare here.
   

10. -Gaming. Oh, THAT old chestnut! Sure, there are tons of games for Mac. Just not the latest and greatest. Or at least nowhere near as many as you get for PC. And you may have to wait a while for a Mac version. Also, you’re limited to videocards that come with your Mac, which (for all the prattle on the Apple site) tend not to be the latest and greatest models on the market. Still, PC games tend to be released later than console-versions too and there is some cool stuff out there for Macs. Or you could dualboot to Windows and have no problems at all. Besides, shouldn’t you be working? I mean, you need to save money for a MAC for Pete’s sake!
    
    Still, there’s good news to: Steam, the game distribution service from Valve software, is also available for the Mac. That doesn’t mean every game on Steam is now available for Mac, but a couple of good ones are (Half-Life, Team Fortress 2 and Portal 2 for instance) and if you bought them to use on your PC you can get a Mac-version for free. So that’s nice!
    

11. -Sadly, you’ll be a Mac-person from now on. Going Apple is not unlike converting to a religion and those who converted when adults tend to be the most preachy. Ahem. I know. I KNOW, OKAY!?!
    

Of course, there are advantages too. Read on.