1. Windows
1.1. Pros
1.1.1. Windows 8 Consumer Preview is that it boots quickly, about 8-12 seconds.
1.1.2. Windows does not require you to put in code in a terminal to get some applications and to get them working
1.2. Cons
1.2.1. Windows is the most targeted operating system for viruses and other malware
1.2.2. Mobile initially aimed to replicate the Windows desktop down to the start menu — an approach that was not popular with consumers.
2. UBUNTU
2.1. Pros
2.1.1. Ubuntu has a booting speed at around 12-14 seconds.
2.1.2. Ubuntu has integrated a more casual (and touch) friendly UI, called Unity.
2.2. Cons
2.2.1. Ubuntu staff is helpful but they are extremely limited on what they can do since they aren’t as big as the others.
2.2.2. Ubuntu is about 2 GB where as both Windows and OS X is much bigger.
3. MAC OS X
3.1. Pros
3.1.1. OS X does not require you to put in code in a terminal to get some applications and to get them working
3.1.2. Mac does not require you to put in code in a terminal to get some applications and to get them working
3.2. Cons
3.2.1. Apple gets mad and will look for ways to throw you in jail if you tell them you have OS X on a PC even if you legally did it.
3.2.2. Both Ubuntu and OS X can do basic things but OS X is limited on what it can do.