I would like to know what are the advantages of Windows 7 or Windows 8?

The Benefits of Windows 7

Improved performance

System boot time and application launch times have noticeably decreased.
A reduction in the time required to place systems into and retrieve them out of hibernation mode makes “putting your system to sleep” more convenient.
New optimization tools decrease battery usage, allowing portable computer users more “cord-free” time than was possible with Vista and XP.

Enhanced searching capabilities

New options allow you to look for keywords in documents, emails, attached storage devices, and can also extend the search to networked servers and designated web pages.

Location aware printing

When you connect to a network, Windows 7 will automatically detect your location and select the proper printers for your print jobs.

Virtual hard disk support

Windows 7 can be virtualized, allowing multiple operating systems to reside on a single host machine.
Windows 7 is preconfigured to support Hyper-V virtual machines.

The search function seems better and faster.
Easier to re size or relocate the application "Windows"

As compared to what? Each other or some other operating systems?