Here's an article about cottonseed vs canola....
"What the public doesn't know is that cottonseed oil already has many of the health and taste attributes all the other oils are striving for. The challenge for NCPA is to find out who needs this information. That led to the joint project with Cotton Incorporated in 1997, which found that the casual dining segment might be very receptive to cottonseed oil.
Your neighborhood Applebee's or Chili's are good examples of the segment. Typically, these restaurants may use canola oil or soy oil, both of which have staked claims on healthiness.
“The canola industry has done a good job of promoting canola oil as being healthy,” said David Kinard, director of research and education for NCPA, in Memphis, which represents U.S. cottonseed oil mills. “But what people don't realize is what is bought on the grocery shelf is different from what restaurants use to fry.”
Kinard explained that the canola or soy oil sold at retail stores is typically used only once and is thrown away. But restaurants need frying oil that will last through several cookings and, under those circumstances, canola and soy oil can break down, or revert. When that happens, the oils take on the flavor of the source. “Soy oil may taste like beans. Canola will taste fishy. Corn oil may be musty.”
To extend an oil's fry life for the restaurant, it has to be hydrogenated, a process which creates trans fatty acids. Those trans-fatty acids are becoming a huge negative in health terms.
On the other hand, when cotton oil with its longer frying life finally does revert, “it has a nutty, buttery flavor that blends well with food flavors and won't overpower the food flavor.”