I'd pick the area based on what you prefer to be close to VS where the clients want you to be. No matter where you are they will come.
I would highly recommend the heart of downtown close to Main Street. It is a very underserviced area full of clients, but you need to set up an incall there instead of bouncing from hotel to hotel & advertise that you are downtown. Try to be walking distance from light rail.
If you don't like downtown, Midtown is another great option.
I've had places in both for years, but had to change my incall location once matters in my personal life changed & I needed an incall closer to my house.
But they are both highly profitable places to be with an abundance of things for you to do in your downtime.