Sorry, not sorry...

I'm not sure why you are apologizing. Lots of people wait to confirm rental cars, although there is a risk of cars running out the longer you wait. This is especially if you go with a smaller local vendor and even more so if you want an automatic, although I will say that there seem to be more automatics available in Europe these days.

That said, I have rented from AutoEurope on multiple occasions because they are easy to deal with, it's easy to compare pricing there, and it gives you a bit of leverage if you have any problems with the actual rental agency, as they are good about making sure the agencies follow through and are available 24/7. I would not compare them to Expedia, though, as AE deals strictly with rental cars and Expedia broadens their stretch to include just about every form of travel. I have never booked through Expedia, and very rarely book with any 3rd parties, but I do make an exception for AutoEurope, because it's limited to rental cars and I've always had good service with them.

Totally agree with Mande. After booking, I check back periodically to see if rates have dropped, and have sometimes gotten much cheaper rates as trip became closer. Not always, but worth reviewing periodically.