I rent cars in many cities, and prefer Enterprise because they seem to have the best overall operation (and professionalism). I strongly recommend signing up for the Enterprise points program.
Here's a strategy for reducing your rental costs. I've done this in both the US and Canada.
Well in advance of your (potential) rental date, log into the web site using your Plus account and make a booking. You don't have to pay in advance for the booking, but it locks in a rate.
Then, as your trip approaches, go back to Enterprise and pull up a quote for the same day. Their rates fluctuate daily and you will often find a lower rate. When that happens, I make a second booking. Then I go back and cancel the earlier booking. Sometimes your initial reservation was the best rate, in which case you just keep that. Make sure you cancel any duplicate bookings you are holding!
The beauty of this approach is you can keep locking in lower rates, if you find them, for the identical reservation. I just used this in Toronto to bring my daily rate from $50 down to $33