(And just a nit: Windows is also an OS. What I think you meant to write is "I have now switched my desktop to Mac OS. As a user of long standing of both systems, I've always been amused that a company as market-savvy as Apple has never come up with a better name for their operating system than "OS.")
An even bigger nit is the whole "PC" standing for IBM PC clone and then standing for anything running MS-DOS or Windows. Atari 8bit is a PC. Amiga is a PC. IBM PC is a PC. MAC is a PC. Pretty everything that is not a giant mainframe, supercomputer or specialized workstation or gaming only box is a PC.