My wife and I used Easy Tour Ireland in September 2013. We had the car for ten days of our two week honeymoon trip. The easy tour site is simply a booking agent for Hertz. Once you go through the easy tour site it redirects you to Hertz and apples a discount code. You book directly with Hertz. We had no problems whatsoever and the final bill was exactly what we were quoted. I chose Easy tour because it was recommended by a coworker who had also used them last year. He told me that they had a mechanical issue after they were on the west coast (rented from DUB) and the car was replaced at their hotel within hours.
I found the rental to be problem free and about 40% cheaper than Dan Dooley ( the next cheapest) when you compare both with Super CDW ( included in the Easy tours rate).
I can assure you I am a real person and not an employee, but I definitely found it to be a good experience, and I plan to use them again when I return this year.
A piece of unsolicited advice: the rental car places will offer you a wifi hotspot for €12 a day or so. I was dumb enough to take it. Turns out I could have bought one with prepaid data from any Tesco for about half of what that cost. Live and learn!