As some of you know, I am in tech support as well. Currently we have about 250 Mac's and between 30 and 40 pc's at the site I work at (the company is global). Besides myself, there is only one other tech, and he is not allowed to touch the pc's (he still needs to get closer to my knowledge level on the Mac before we let him near the pc's).
Last year we had our network infrastructure updated to all 100 baseT auto sensing. You know how long it took?? A weekend. Sure, I had to call down to corporate, and have the infrastructure people set some of the switch ports to different settings, since Mac's can automatically deal with Auto sense, unlike older pc's. I had told them to make all the ports full auto sense, but they didn't, hence the need for the phone calls.
I have seen pictures of what the network closet looked like 11+ years ago when my boss started at the company. Back then, it WAS a nightmare, but she got it all fixed up (as fast as they could give her the budget to do so).
As for supporting the different platforms, a healthy percentage of our users here (on the Mac side) are savvy enough to NOT go and f*ck up their systems. Even if they do, most of the time they tell us what they did last, and we are able to get them back up and running in short order. In the 2-1/2+ years I have been working where I am, I have only come across one Mac that has died (motherboard went on a beige G3 233MHz system after many long, hard years of service). On the pc side, several have given up the ghost, sh*t the bed, [insert death saying here]. In general, the Mac's get more use, and are run harder then the pc's. The pc's are for the business, financial, and HR departments. Where the designers, page production and all the writers/editors use Mac's (of one flavor or another).
We are in the middle of a RAM upgrade for just about everyone on G3 systems (iMac's and blue and white systems) so that we can migrate to OS X. It is going to be a hell of a lot easier then switching someone from win98/nt4 to 2k.
In my [professional] experience, the people that bash the Mac the hardest, are the same ones that would never consider using one. Hell, even my cousin, who is also in IT, is talking about getting an iMac so that he can learn about them. He knows windblows and linux, but wants to learn about the Mac and OS X.
BTW, I have a game pc here that I built (there was no way I was going to buy an intel powered system *cough*crap*cough*) and it is not the first pc I have constructed. I also provide tech support for people on the side, and the only reasons I don't get a ton of repeats are that just about all of them (except for one person) are on Mac's AND I know what the hell I am doing. I had a repeat a short time ago, after not working on the system for over a year. The woman's daughter put a smudged cd into the drive, and then it acted up. The drive had heavy fragmentation, and some damaged directories. I was finished with the blue and white G3 after only a short time, and even ran several updates on it (software update control panel is many times better then the windows update item). In under two hours, the woman had the computer back, fully functional. As always, she was very happy with the service. I also periodically check on my customers to see if their systems are running good for them, as a courtesy.