Crossover is an alternative approach to run Windows applications in another environment (OSX, Linux). Not by running Windows, but by fooling Windows applications that they are running inside Windows. It uses Wine (an Open Source system - Wine Is Not an Emulator - typical Linux recursive acronym) but packages it in a more user-oriented and friendly application. You don't really need it, but it makes it more convenient. While initially focused on gaming, it has fair support for many business applications too. Each application is (or can be) installed in a separate "Bottle", isolating it from others. Performance was adequate.

CrossOver is a help to Linux novices who can't or won't leave certain Windows applications behind. CrossOver probably doesn't do anything you couldn't do yourself with Wine and some time/expertise/willingness to tinker, but it does simplify the task of getting Windows programs installed and running virtually on your Linux computer. They have an extensive list of supported programs and a Bronze/Silver/Gold medal rating system that describes how well programs should be expected to work, so your expectations are set up front.