Otherwise, Parallels Desktop is a solution to install Windows or Linux programs or the respective operating systems in parallel and to run concurrently with the primary system. Anyone who wants to can start the Mac, then start there Windows in a window or Windows programs on OSX use etc ... alternatives are VMware Fusion and Virtual Box and the Apple Boot Camp solution.
The integration is very good if you Windows 7 or 8 used- there the context menus are added to Mac-specific options. The direct data exchange between Mac and PC integriert- is very convenient. Windows programs also appear in the dock and can be started from there.
For simultaneous work with Windows and the hardware Macprogrammen should be a bit better than the Mindestanforderungen- 8GB of RAM for example, would be nice. The expectation that all Windows games run under Mac OS in the virtual box is also not confirmed in any case.
In principle, it is worth Parallels Desktop especially for those who do not feel confident to set up a system with multiple operating systems and who want to have direct data exchange. Otherwise, is already included in Mac Os Boot Camp, which also allows you to install Windows on OSX.