Well... actually they are ultra-flexible in architecture. They're a UNIX-based box, so you can do almost anything with them. It's Windows that traps you.
Its not the OS, I dont care about the OS, I have no experience with Unix or whatever apple uses, its the apps I care about. The only experience I have with apple specifically regarding OSs is apple apps hard crashing on a PC... OK, they dont crash on a MAC , again, I dont care about the OS or hardware, I just want to run all the apps I need fast. I have MANY apps that done run (natively) on a MAC.
"General, every day use?" They are being used by some of the most demanding users there are - in publishing, science, engineering and high-end graphics.
What I mean by "everyday" is apps running as is out of the box, regardless of complexity, designed for MACs. I have many apps with obscure IO that apple just doesnt address, thats the key, apple works with minimal/proprietry IO fine. Its not apples fault, but much odd IO is not made for MACs, as the authers only write drivers once for the most common OS, for low volume products.
Like this? My 27" iMac QuadCore running OSX, Vista, MaximDL5, Registar and PHD Guiding all at once and without raising a sweat... and that's just within the running Windows environment. At the same time I'm also running Photoshop CS4, Safari browser, Mail, Pages (a word processor), iDVD and a QuickTime movie on the Mac side - all concurrently and all at a pretty reasonable clip. My QuadCore PC with same basic characteristics wouldn't have a hope.
Oh please, why would I bother with a simulator when I have the real thing

(and minimal use for apple apps). Im willing to be proved wrong, but would CCD stack run faster and cheaper in win sim mode than a quad core i7 with win7 pro?.
In the end, I run email, MYOB, IIS and other boring non-speed critical stuff all day with no fuss. My experience with (2) apple apps is woefull, and anyway they run OK generally on a win PC. Id like speed with PS and CCDstack and thats about it.
So why, oh why, would I even think of bothering with a MAC, with the extra cost, more drama, less compatibility with the apps/IO I have (without .....ummm, running a win simulator

).