I was a fan of Ariel so much so I joined VG for her, but stayed for the many great models, I personally love her as a person first, she's got great energy and really has fun with "putting on a show" in whatever modeling she's doing at the time.
As for the hair... I like Orange ok, but feel her Red catches her persona much better and she should go back to it, I have never been a fan of fake-ness in models but her Red never really bothered me, I think mainly because it matches her personality so well to have a slightly crazy hair.
And lets be honest and face it, she can always let the real color grow out if she wanted, its not like its a tattoo or breast augmentation, which there is no coming back from.