I (used to?) own a student license for Parallels Desktop circa 2012, though it may have expired by now.

In my experience, I could see no major differences between their solution and, say, Virtualbox. There were some Mac-specific features like working well with Exposé when in Seamless mode and a few other UI niceties, but Parallels seems primarily geared towards supporting Windows. Linux Guest OS support of features like Seamless mode refused to work unless you had specific kernel versions and was always several versions behind in my experience. I'm sure the feature parity gap between Virtualbox and Parallels Desktop is even smaller today than it used to be.

The pricetag is usually less for Parallels products compared to the leading commercial competitor, FWIW.