I use Kubuntu (might as well be Ubuntu, because I've installed Gnome, and use it primarily) at home. I use Windows and Mac OSX, and many varieties of linux at work.
- The ability to fully customize my firewall
- The ability to get in the guts of the system, and tweak it to my hearts content
- The ammount of free software out there for it
- The inner workings of the system are not as easy for users to understand
- 3 words: "make && make install" (I prefer this method, but it's not for everybody)
- Their GUI needs some work
- A HUGE library of software, easily installable, at your fingertips
- You don't need to be a super geek to learn it
- Games play better on it
- Not free. Not anywhere close to free
- Virus anybody?
- Why does it get slow after 6 months of use? Time to defrag the registry (the registry is memory resident, and when it gets corrupt, it slows the system down bad)
- The base of the OS has way too much processor and memory overhead
- Spyware anybody?
- Sleak inviornment
- Easy to install software
- Great support
- has many of the features of linux
- To get those great features, you got to be willing to "break Mac rules". Actually, they aren't rules, but Apple sure didn't make it easy to get to some of those settings
- Not as much software as linux and Windows available
- Big cost factor. If your computer is more than 2 years old, chances are you cannot upgrade to the latest version of the OS.