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The point is that I'm searching for a new computer, which I'm gonna use primarily for statistical modelling, intensive spreadsheet compiling and processing in MS Excel (with more than 500,000 rows) as well as occasional running of MS Access for database management....
You don't have a dilemma. Or, to put it that way: Your only dilemma is that you WANT to buy into the hype and buy Apple hardware although you already know that your software requirements clearly say that you need a system with Windows on it (which is usually defined as a "PC").
You need to run MS Access. Well, you have my sympathies - because MS Access probably is one of the worst pieces of software on that planet - and I am NOT a Microsoft basher, just a guy who makes his living in IT and grew to hate Access and its infinite number of bugs with a passion. But you need it, and MS Access ONLY runs on Windows. There are no OS X or Linux versions of Access. Or of Microsoft Visio or Project, for that matter.
So you --NEED-- Windows to run the software that you --NEED--. Which means that you do NOT have a business case for Mac OS X - rather the opposite, you have THE perfect case AGAINST buying and using Mac OS X! Really, where is that dilemma you were talking about?
Okay. You can buy a Mac, wipe out OS X from the hard disk and happily use your Apple PC with Windows ONLY. I actually know people who do that, it is not uncommon or unheard of. It just doesn't make any economic sense, because you pay MORE for the hardware and then you also pay MORE for the software (because you have to buy the Windows license on top of the already expensive hardware), but it can be done. And it works very well. Apple hardware is very compatible with Windows, and 64-Bit Windows 7 runs GREAT on Macs.
If you go down that lane, I recommend buying an OEM version for Windows 7 IN GERMANY. I just paid 45 Euros for a Win 7 Pro RE-INSTALLATION DVD with a Dell Win 7 COA license sticker. IN GERMANY, THIS IS LEGAL. But unfortunately for you, as far as I know, Germany is the only country on the planet where Microsoft's licensing policies have conflicted with the local law. If you want to purchase OEM licenses in the US, you might run into licensing issues with Microsoft and have to buy the much more expensive retail boxes instead if you want to be 100% sure that your license is valid. But in Germany, Microsoft had lost their case 12 years ago and since then license transfers are fully legal and so is re-selling "used" software or the use of Systembuilder/OEM software without bundled hardware. That's why you can get a fully valid Win7 Pro OEM license for 45 bucks here.
But back to the Mac and Office. The OS X version of Microsoft Office is no match for its Windows sibling. The Windows versions eat Office:Mac alive and swallow it down in one piece. It's not even a contest. Office:Mac is a slow, buggy, handicapped crutch with less features when compared to Office for Windows. And it doesn't matter WHY this is the case or who's to blame or whose fault it is that there is no viable alternative to MS Office on the Mac.
The Mac is NOT a corporate/enterprise/business platform. It never was, it never will be. You need a business desktop/notebook, you use a Windows machine with Windows software. Apple only ships consumer and home user products, that's an undeniable matter of fact. They don't even cater to their once favored target audience of movie and music editors anymore.
There are many cases where you might get a Mac and OS X to work well enough in the business world, but the feasibility of this is usually very questionable. It's usually not worth the extra money, time and effort.
I can understand if you love the design of Apple hardware. I do, too. If you want to spend the extra buck on the design, do it. Linux runs great on Apple hardware, and so does Windows. But with your business needs, don't expect OS X to become your best friend - ever.
If you buy that Mac, buy it with a Windows license.