I have attempted to install Ubuntu Linux 18.04 LTS, but Parallels Tools fails to install due to the inability to build one of Parallels' kernel modules (for the Linux 4.15 kernel). Adding support for that would be something I would like to see! Thanks!
When there are new Versions of parallels, virtualbox and vm ware with 64bit guest additions I will recompare and probably swich all our Macs to vm-ware or virtual-box. It is no fun to switch to an other vm just to test the newest version of ubuntu !