No trouble at all, everything works and I even have 2 finger scrolling
i purchased a Dell 9 just to put OSX on it, as it is the easiest to get running, and it uses a legit retail copy of OS X Leopard, not a hacked one from a torrent site, so apple gets it money for a copy of leopard.
It for the most part has been flawless. It works great for general web surfing and email (keyboard layout sucks.) I even have some older games running on it. All OSX updates work fine, so does iPhoto, iWork, iTunes.
Everything works using the Dell EFI method with threee exceptions, Hibernate (save state to hard disc) and the external mic plug. To turn off the bluetooth wireless, you have to go into the bios (or just leave it off and use a USB bluetooth and remove it instead.) Everything else works, including sleep, wireless, system updates, etc.
An improved two finger scrolling is in alpha right now, I think it will go into beta software in a couple of weeks. Many people are using the alpha software without issues. (I'm waiting for the official release with DellEFI1.2)
A Dell 9 does have a couple of issues I have noticed however. First of all, some windows that can't be resized open too big. This can be mitigated with a program called scaleres however.
The second isssue is that the CPU lacks power for 720p video (even if played in a window). (I did do some dvd video converted with handbrake, it ran that fine.) Hulu plays choppy, I would assume because the flash version on OS X has always been a resource hog. Movie trailers played from the build in frontrow work great however.
The keyboard is odd on that machine, it can be replaced with an international english keyboard that is suppose to be better, but I haven't done that.
My setup is a Dell Mini 9, 2 gig memory bought from Newegg, and a stock 32gig SSD drive, with bluetooth & 1.3MP camera. I paid $350 total for it, excluding a copy of leopard.
Would I give one of these machines to a nontechie? Nope, too much chance a system update might break it, or some other issue. I think anyone who is reading these forums would do just fine with the Dell 9 OS X however.
Would it be a great day computer, just to throw into a backpack, a student to take to class, etc? That's my plan. I am hoping to travel with it instead of the heavier macbook. My macbook gets trashed with all the travel in my job, I would prefer to risk a much less expensive computer instead.
If you buy one of these when you need a full laptop instead you will be disappointed. If you want something greater than an iPhone, but less than a full size laptop, this computer running OS X is great for that job.
Oh, if anyone is interested in specific steps needed for running os X on the Dell 9, here is the forum that will help you:
http://www.mydellmini.com/forum/mac-os-x-f23.html