I used to run BeOS on one of my PPC Macs, back in the 90s. I liked it a lot. Haiku is just like it.
I dual boot, with Windows 7 and various Debian distros. I also occasionally run Android in a VM. If I were heavy into recording or graphics design, I might consider a Mac, but it's not worth it for me and for what I do.
By the way, I can, but don't dual boot. I'm using Parallels desktop and VM Ware Fusion. I can also run Android apps, but I have no use for that. I like iOS a lot better.
But the point of why a Mac?, is never having to run Windows! It's an awful operating system. it looks nicer these days, but it's a PITA. Linux is kind of nice, in a clunky sort of way, but the GUI is primitive, and there's not a lot of GOOD software for it. Mac OS X is what Linux (and Windows) wants to be when it grows up. It's at 10.8.4 now, which is really version 18.4. Windows is at 7, and is still Win NT.
I run these other OSs so I know how to use them, and because it's fun. But I never use them for any real work.
Being the "computer guy" I'm constantly fielding questions from friends with PCs when things are not working as they should, which is on a weekly basis. (My Mac using friends have very few problems with their computers.)
I have to keep saying "hmmmm, I don't have any problems like that/didn't have to jump through those hoops/to use my printer/get on a network/synch my iPhone, etc." Windows does some agonizingly stupid things. lol But most PC users have no other point of reference so they think it's just the way computers are. They are supposed to be counterintuitive and overly complicated!
My (now ex) wife was so tired of her dad calling me for help with his Dell (had to reinstall his printer drivers every time he wanted to print), that she insisted he get a Mac. After a week of getting him adjusted to the new OS, I never heard from him again, as far as computer questions. Then he liked it so much he got an Apple Laptop. Macs just work. No dicking around needed.
As far as them being more expensive, yes, you can get dirt cheap PCs. But they generally don't have very long lifespans. The guitarist in one of the bands I play in has to get his wife a new laptop. Her two year old HP has many issues. The power jack is lose, the trackpad doesn't work well, and other things.
Meanwhile my son has a four year old Mac Book Pro, which was a refurb, and he uses it every day, all day long. Not a single thing has ever gone wrong with it, except when he spilled soda on it and a DVD got stuck in the drive. But we fixed that ourselves.
I use an early 2009 iMac, with 2.93 GHz, Core2Duo, 8 GB of RAM and a 1TB hard drive. It was also a refurb. It replaced my G4 tower which I bought in... 2001. So they might be expensive, but they last a ridiculously long time. This does everything I need from general computing, to Photoshop to Pro Tools/Cubase, etc.
I don't hate on Macs; I was just trying to figure out what was meant by his comparison to the Fender 5-string.
I don't know what that was about either.