I was a Windows user for a long time but decided to see what the hype was about Mac's so bought myself a Macbook and never went back to Windows (that was about 8 years ago). For three years now I've had a Macbook and it's still working great. Has not slowed down or anything and I've got tons of photos and graphic art stuff on it. Of course, I also have 3 external drives and use two of them all the time (one for RAW photos and one for graphic design). We still have a Windows computer at home but the kids used it for games and then it died. Just wasn't powerful enough for gaming. But what we had wasn't designed for gaming so it totally makes sense. My daughter has played some of her games on my Macbook but I really don't allow it because it will slow it down immensely. A gaming computer has to be built for it. A regular Macbook or Windows PC will not work.
As for Macs and PC's, it's just preference. Some people have bad experiences with Apple products so they avoid it. Some just switch to see what it was all about (like me) and end up liking it...and I'm sure some switched and didn't like it and went back to Windows. Personally, I've always wanted a Mac, because most artists use it for graphics designing and other artistic things, and hardly heard them complain. Now that I have one, I totally understand. It's a brainless system and so easy to use so you can focus on the art.
As for the mouse and keyboard, I use both wireless and I like it. I have to switch out batteries every now and then (I use rechargeables) but it's no big deal because I like my space without all those wires.