Lightworks is a Windows program. Powerful, fully-featured, it's a precision tool that lets you edit with incredible efficiency. It's available as a free download and is currently in an advanced Beta phase, while it is tuned to run as a software-only application. Prior to this version, it was sold only as a turnkey system.
Can you run it on a Mac? Not as a native OS X application: it's strictly Windows at the moment. But, yes, you can run it on Mac hardware, by dual-booting into Windows under Bootcamp. Bootcamp drivers do a very good job of allowing Windows to use all of the Mac's resources natively. Intel-based Macs make very good PCs.
If you don't like Windows, Lightworks uses it's own interface and conventions that are focused on editing and optimised for it. You won't see much of Windows while you're in Lightworks.
We have heard reports of Lightworks running under virtualisation using programs like Parallels. This may work, and work well, but it is always going to be harder to support when there are issues. It is also likely that performance will suffer.
What about the Mac-native version of Lightworks? It's on the roadmap, but it's a long road. Don't expect it soon. Porting to another OS is a massive undertaking, but work is underway. However, during the current Beta programme, the focus of our developers' efforts will be on making the Windows version "match ready". Watch the Announcements section of the forum for more information on this.