Compare? Simple. Take Photoshop on a Mac, take Photoshop on a PC, run the same filter. See which is faster. Of course you'll use other applications as well (whichever matters to you). If the software you want is only available for Windows or MacOS (like Final Cut or 90% of the games out there), then really, it's not even a choice anymore now is it?
"We are Microsoft, resistance is futile." - Bill Gates, 2015.