I agree with everyone who likes them... I actually definitely prefer a colorfully toned coin over a blast white one.. and will absolutely pay a premium for one I like. But there's a difference to me between brown/black (ugly) toning compared to rainbow colors, either single colors alone or actually a rainbow together... Colors yes... Ugly no... Unless its on a very very old coin I would expect to find it on.
How is toning damage? I agree with GoldenChest, but I'd have to say that even if it was made in an artificial manner then I'd still call it altered more than damaged. I wouldn't pay a premium for an artificially toned one but do own a few that I like. Toning is a completely natural process that happens to metals when mixed with natural elements found on every millimeter in this world. So again, how is that damage if its a naturally occuring process? There's really no way to completely stop toning, delay it sure.. But one day all coins will tone... Like it or not, lol.