I've used cirtus degreasers and they work well, but have used WD-40 to clean my chain when I've been out of degreaser. I think it is mainly recommended not to use WD-40 as your sole chain lubricant. It seems to work well as a cleaner while leaving behind a bit of lubrication. I then put on Finish Line Dry Teflon lube, or whatever lube I currently have.