There are subtle things like overall smoothness of operation, rather than performance under load.
I find Windows on a HDD unpleasantly jerky, sometimes even on SSDs... not an issue with Linux.
Modern filesystems available on Linux have their perks beyond performance, if you want to get into them (e.g. snapshots).
Looks are trivial, especially in Linux. There are hundreds of interfaces available, the big mainstreamy ones including Ubuntu's Unity may not seem to different from Windows/OSX, but if you want minimalism or a high degree of configurability you have interesting other options (which will admittedly need some time getting used to).
On the technical side, I have far more respect for Linux than Windows. Linux on the whole is less hassle than Windows... but if you're familiar with the woes of a Windows user and can live with it, getting used to the woes of a Linux user may not be worth the effort. Whether the change is practical depends on your priorities, and what software you run.
Free Software is generally much more pleasant to use on Linux - you have a package manager (somewhat similar to an app store) taking care of installation and maintenance, without hunting for downloads, removing the crapware you accidentally installed alongside, and all the other hassle.
Commercial software often isn't available on Linux or doesn't get the same attention. Windows-exclusive software can often be run under WINE (a compatibility layer), but that can be unpleasant (bugs, goat sacrifices required to get things running, performance hits).
Linux is great, but not for everyone.