We actually have a few macs still on the networks, and they work fine. The macs never were, and still are not, connected to a file server. That's part of why they were so easy to work with. All they needed was an internet connection, and we were happy. No malware, no slowing down, they just worked. We fought for years to keep them, but we eventually lost after a few years. And judging by the number of times the network goes down, or slows down, each week, I imagine managing an all windows network isn't a piece of cake either. While the network is much better for the PC side these days, it is still a pain in the ass when they decide to work on the server during working hours (we are operating 24 hours a day, every day).
The Reason your IT Department got rid of the macs is the inability to manage macs in a Windows Server environment. It takes 2 times as much work to get Apple to work in a windows environment. and it also costs a lot of money to get the software to put Macs in the Active Directory and to be able to use scripts that map drives and printers. Yes I am speaking from experience. The Mac's may be easier for the end user to use but they will be a pain to the Administrators to manage.
Macs come with multi-button mouses, and have for a few years now. And even when they didn't, buy a $15 mouse at Best buy. I haven't used a one button mouse on the mac since about System 7 or so.
But in the end a PC user is not going to convert to a Mac user unless they are up to the challenge of learning something new. Just the same applies the other way around. If you enjoy a single button Mouse stay away from Windows if you don't like a single button mouse stick with windows. If you enjoy computing go with Linux there you will have the best of all three computing worlds. Linux can be what you want it to be. If you want simple look at Ubuntu. If you want complex look at Slackware. If you want UNIX install any distribution and remove the x window system.