You should use Ubuntu if:

If you use:

• Word processor
• Web browser
• Music player
• Basic photo viewer/editor

If you do not use:

•  Games (beyond your extremely simple 1980’s arcade style games)

If you:

• Have a limited budget
• Someone who can set it up for you
• Do not want to worry about viruses

You should use OSX if:

If you use:

• The Microsoft Office Suite
• Web browser
• Music player
• Advanced photo viewer/editor

If you do not use:

•  Games (Unless you are willing to install Windows on your Mac)

If you:

• Large budget
• Want a laptop
• Do not want to worry about viruses

You should use Windows if:

If you use:

• The Microsoft Office Suite
• Web browser
• Music player
• Advanced photo viewer/editor
• Games

If you:

• Have a limited budget
• Want to be able to run pretty much every program ever made
• Are a savvy user who can avoid getting a virus