Fresh Dev purchased Helpdesk from KREA in January 2016, so we haven’t got any direct testimonials. There are 2 publicised from DevDemon and if you’d like to learn more about our add-on from a third party, you can find a very robust review of HelpDesk at EE:insider.
There are also older reviews on Devot:ee.
“We have loved the move to this add-on. We use it at Dev-Demon to manage all of our support. The system has been crucial to managing our support requests. We attempted many hosted solutions and found this solution to just be the most affordable and easiest to manage.” — Brad Parscale, DevDemon.com