Elessar,
How well your OS "performs" is not really a consideration. The usefulness of an operating system is determined by how well it enables you to do what you want to do.
I use Linux extensively as an inexpensive network staple in my work. It serves that purpose very well, by providing routing and packet filtering / manipulation capabilities that simply blow Windows out of the water, and could only be matched by high end specialized products with 5-digit price tags.
As a desktop OS, it will work great for you if you need your computer to perform specific tasks (browse the web, read email, write papers, create websites and graphics, etc.) and you don't mind learning to use new software for these tasks (different from what you've got used to on Windows).
Most Linux software is free, which can be a benefit -- if you couldn't afford Photoshop for Windows and ethical concerns prevented you from stealing it, then gimp will definitely be an upgrade to whatever you were using (there is gimp for Windows too, but let's pretend there isn't
).
Linux on your only / primary computer won't make you very happy if you are a gamer or like to try out all the latest toys your friends are using (such as WLM beta). It wasn't made for running Windows software, even if that's sometimes possible through various emulators. In that regard, Linux is similar to Macintosh -- you are in a world of different ways and different software.
