The k-girls who work on Sundays tend to be the newer, less experienced ladies. Some of the 3-month wonders work 7 days a week. I don't know how they handle such a brutal schedule, but they do. Given that, I tend to reserve Sundays for trying out ladies with no reviews or very few reviews. (Only if they are handled by trusted bookers, of course.)
Sometimes you run across undiscovered gems that way, and they aren't yet jaded or sick of the job. They are trying to establish themselves in a very competitive market and so sometimes they will show you a better time than a lady who has been around for a while. Not always, but sometimes. Still, it's fun to try. Makes my heart pound a little harder when I arrive at the door, not sure of what I will see on the other side. It's kind of like throwing a Hail Mary pass. When it works, it's amazing!