"It’s often the case that the clients that pay your lowest rate are the biggest pain and the least loyal."

Boy ain't this the truth. I had a client last year that nickled and dimed me and every other vendor they have. It's their way of doing business. Then they stopped paying on time, claimed it was due to the economy. Thing is whenever they got a new sale they would ring a bell, once for every $1000 of the sale. We had several days each month where the bell did not ring less than 10 times. On top of this they expected me to perform duties that I was not contracted to perform i.e. man customer support phones, I'm a developer. I ended our relationship at the end of the year and haven't felt better about any decision. Good riddance.