Latest issue of Distrowatch weekly news letter includes a review of Zorin OS 10 Core, which is a Ubuntu based GNU/Linux distribution offering windows like user interface. Zorin OS 10 is based on Ubuntu 15.04.
This review remarks that, despite of some performance issues comparing to Zorin OS 8, Zorin OS 10 is a perfect GNU/Linux alternative for windows migrants.
Zorin OS is a GNU/Linux distribution that attempts to mimic the appearance of the Microsoft Windows operating system. I gave it a go roughly about a year and eight months ago (Zorin OS 8 Core) and my general impression was that it succeed in doing so, meaning that it was quite appealing in the eyes of a Microsoft Windows user.
However, back then I compared it to Linux Mint 15 Cinnamon edition (because they were both based on Ubuntu and looked very similar) and after considering the performance (boot-up speeds, memory usage, etc) and features of both operating systems, I still preferred Linux Mint 15 Cinnamon. But Zorin too did not lag behind by too much, it was mostly the lightweight memory usage and the boot-up speed of Linux Mint that took my attention.
In other words, features-wise, they were both good, but Linux Mint was better in terms of technical implementations, because I just had the impression that Linux Mint had taken in an Ubuntu core, stripped down all the unnecessary aspects of it, optimized it to suit their needs, and had implemented their own desktop environment on top of that.