I have a dark golden (red) field bred and I have an FC/AFC bred boy that's medium. The field breedings get tagged for the dark colors, but honestly there are dark conformation dogs as well. We have two conformation breeders on here that I know have darker colored dogs. pick a dog that will fit your lifestyle and not one based on color. The color will not matter once you have the dog. If you're dead set on a color you need to first decide your activity and commitment level and then look at the parents of the litter. You are going to get a range of color in any litter based on the parents. If you're going to have a color preference you're going to have a much longer wait to get what you really want, unless you're putting color above everything else.
My two field breds are high energy. One has an amazing off switch and is a couch potato as long as he gets some exercise. He gets at least three hours a day of off leash exercise (when he's healthy). My other field bred has absolutely no off switch at this time. (out of FC/AFC Emberain Beau Geste) He's 100% on every minute, and it doesn't matter how much exercise he gets. He is not for the average house and he is not for the faint of heart. He is 9 months old and can run 100 yard marks over and over and never even breath heavy. I honestly need the weather to break here just to restore my sanity. I ran him yesterday three times in the pouring freezing rain and wind just to be able to keep up with him in the house. Is this typical? Not in my experience, but I was prepared for it. I love him and he does cuddle for a second in between adventures. I live on a farm with lots of room to run. I can't imagine the trouble he could get into without proper exercise and training. He's super independent.
My conformation boy can run right along with them but he calms down the instant he goes inside. He is easier to live with.
My dark boy had both dark parents (red). My light field bred had a dark (red) and a medium parent. My conformation boy had a light and a medium parent. Color wasn't a concern.
I will admit that if a really nice dark conformation boy ever comes available to me I would probably be excited. The color would still come way down the line after health, proof of versatility in the line, bone, pigment, structure, head, tail carriage, foot shape..... You get the idea. I'll probably have to start putting out feelers now to get one when I want one. Trust me with this puppy I am not in the market anytime soon! (shew) The funny part is that while he drives me a little crazy I look at all his crazy antics and all I see is potential. Keep in mind we bought him to be an addition to the family but with a true goal in mind, not just a pet.
Posting pics so you can hopefully see that there is more to choices then the color.