Hotwire car rental

Never used it. But if Hotwire lands you a deal with a "bad apple" car rental company (like Goldcar in other parts of Europe), you'll regret it.
Among consolidators, Autoeurope gets most people's "vote" here, including mine: you see who you book with, prices are almost always better than directly through the renters, include access to a dedicated customer service, and come with flexible cancellation.

We did book through Hotwire back in May 2017. And the rate was honored. Hotwire reserved our car with Europcar, and our car was waiting for us when we arrived. However, it took a very long time for our collision damage waiver (based on my MasterCard) to be approved by the car rental company. It took my calling back to the U.S. and conversations between two of Europcar's rental agents and at least two staff members at Barclays for Europcar to accept that the CDW would be honored in the Republic and in Northern Ireland. Europcar also placed a $5000.00 hold on my car for incidental damages. (I went back to check an old post on these forums to be sure of my details.)

So I would book with Hotwire again. After booking, however, I would contact the actual car rental company and ask if there is anything further required by you to ensure a smooth pick-up and drop-off.