considering how pointless it would be to argue about color, I think it's great that the owner went for something unique. I've seen one in Dakar Yellow in UK btw, so it's kinda of showing that the owner knows his BMWs.
Were I to do the same I would go for my favourite color - Avus Blue... my old E36 was that color and I just can't get over it. Le Mans Blue is just not the same.
On the custom color for 5000 bucks I think that actually one might get better results by ordering a professional respray in a top notch shop, with good paint, etc. BMW puts very thin layer or paint these days on their cars, they chip easily. I hope that this won't happe to this one, but personallly I would have gone with pro paint shop.