I have used Exterro at a couple of instances. I've used Exterro throughout my internships as a digital forensic consultant, as well as using Exterro, specifically the FTK Imager and FTK Toolkit, to teach my students in the digital forensics class I teach.
I mostly use Exterro for teaching. I usually give my students labs with digital forensics labs where we start off with trying to image the disk at hand, and that's where I use FTK Imager. I usually teach them about hashes, how to image, how to get registry, or even how to analyze memory by taking an image of the memory. Then we go on to analyzing the disk image to find deleted files, recovering artifacts like browser history, emails, and registry keys. The whole process is divided into several labs that I give to my students.
Exterro has been the very first tool I usually introduce to my students. Most of the time, my students come back and say that it's very intuitive. Since it's been the very first tool that they get introduced to in the class, it usually leaves a very lasting impact on them. Using Exterro in class has been really helpful in getting students to understand the fundamentals. I use Exterro as a live teaching tool rather than having a simulated environment. Students actually go through and use Exterro with real forensic disk images and practice the same workflow as a practicing examiner would.
I know this because I actually used Exterro for my internship. As a digital forensic consultant, we used to analyze all sorts of cases using Exterro, the FTK Toolkit, and the FTK Imager. I try to use the same workflow and the same methodology to teach students who are going to become digital forensic analysts using Exterro. This has been one of the most heavily used cases for Exterro.