BigGuy and all others concerned,
I completed my rental and instead of the stated 15% that I was supposed to receive over the regular rates, it came to 27.7% !!! That is why it was better than the 20% coupon from the Entertainment Book.
Now, hopefully, I will receive the 1,500 United miles for the 5 days or longer rental!
I will keep you all posted.
Of course, YMMV when using this code.
Good luck!