1. Windows 7
1.1. Pros:
1.1.1. Smalll size,but not quite as small as Mac OS X
1.1.2. Use the right mouse button and tie them to the new style taskbar. No Quick Launch.
1.2. Cons:
1.2.1. Slow boot time. Errors in booting up.
1.2.2. Very minimal protection for users.
2. Mac OS X
2.1. Pros:
2.1.1. Faster boot time than previous versions
2.1.2. Exchange support across Mail, the Address Book, and iCal is great for business needs.
2.2. Cons:
2.2.1. Snow Leopard works with Intel Macs only; unless you buy upgrade.
2.2.2. Less protection against viruses, and bugs.
3. Ubuntu 10.10
3.1. Pros:
3.1.1. Ubuntu 3D multiple desktop is aesthetically pleasing, and more organized.
3.1.2. The 'Always On Top' feature allows you to keep a window on top of all the windows, even when switching between windows.
3.2. Cons:
3.2.1. Slow boot time. Installation time very slow.
3.2.2. Most changes are visual, not as big difference from last release.
4. Chromium OS
4.1. Pros:
4.1.1. Solely web-based
4.1.2. Encrypted storage of all user data in the cloud
4.2. Cons:
4.2.1. Becomes unresponsive in both VMWare and VirtualBox if left unused for a few minutes.
4.2.2. Aesthetically simple