I have it and hate it. I can't ride or run when it is cold outside. My fingers freeze and lock no matter what kind of gloves I wear. I have been on the verge of hypothermia from it several times only to find myself crying from the pain when my fingers began to warm up.
My brother has it. His fingers go white and numb mostly when he's riding his motorcycle. He can put his left hand on the motor to warm it up, but can't do anything for his throttle hand. I have poor circulation in my hands, but not as bad.
I have it. It sucks. Keep fingers extra warm, change positions a lot, and toss chemical warmers in your gloves when it's cold. I've found that keeping your forearms warm helps a lot. I wear lobster mitts when the temps drop below 30. Looks ridiculous, but it's better than the alternative.