1. Performance statistics are easily slanted towards whichever platform you prefer. They are highly dependent on the hardware and configuration.
2. All three allow interchange of data files in common or open document formats.
3. Price is the only objective factor that can be judged. Lowest price entry points are cheapest for Linux, followed by Windows, then by Mac.
4. The other factors which truly determine which one you use are subjective. If you want to play games, Windows is the primary platform for most computer games. If you want to live in the sleek, futuristic, streamlined world of Apple and have stuff "just work", then choose Mac. If you want to tinker and tweak and customize your system, choose Linux.
Anyone who argues that one is better than another is like saying one kind of fruit is the best.