First, let’s just point something out here: you have to start your rebuttal by disregarding a huge factor in this debate. That’s a huge concession that, I think, shows how weak your position is.
Moving past that…
I don’t see any benefits to switching over to Macs. I don’t see them as being more performant, more usable, or otherwise superior. They get hacked first in most hacking contests. And like I said before, you’re basically paying for a cool looking laptop. If you really want the mechanics of Mac OS X, go get FreeBSD (or PC-BSD, which is the former but with a desktop environment on top) and install it on just about anything you can cobble together, because that’s what Mac OS X is built on. Best part: you won’t be paying $300 for the OS alone and can certainly save hundreds of dollars.
What is it that makes a Mac OS experience so much better than Windows? The dock? Pfft. You can have the dock if you want, though you will usually make that unusable when you try to get all the programs you use on there. Finder? What’s so great about it? Better graphics? Wait — you mean on your desktop? Right, because having your window shimmer into view or wiggle off your dock is such an improvement. (If you really think that’s a plus point over Windows, sorry, but I won’t be able to take you seriously.) No virus issues? Again, Mac OS X usually gets hacked first. You’re basing your entire defense on “security through obscurity,” which is getting worse and worse by the hour. And for the record, I have seen friends send their Mac computers into kernel panics – the grey screen of “oh s—” – as recently as 2011. Windows BSOD? Haven’t seen one of those since 2005.
Is it customer service? So you can go to the “Apple bar”, not even get an Apple martini, and wait for some smug dude to tell you to spend an extra bunch of cash to fix this or that? Or you can, you know, Google. Saves you time and money.
Finally, again, there is flexibility. With Apple, you are essentially locked into a handful of computers at a handful of price points. Now maybe you don’t want to have choice, or better still, want someone else to make most of the choices for you. But with Windows, it runs on just about anything, so you can make any type of build, from budget desktops to screaming laptops and mobile workstations that double as servers. You can’t get that with Apple — at least not without violating the EULA and doing some hacking to make it work on hardware you can’t get from the Apple store. Sorry, but after building computers, I’ll take that route. I understand that’s not for everybody, but that’s a huge plus point over Mac OS X. And you can get a ton of different configurations for less money at places like Newegg and Tigerdirect, Best Buy and Target. Apple? Not so much.
(Edited for paragraph spacing.)