I think the problem with this study was that the object you were referencing was a very smooth and very reflective object. So everything in its surroundings are clear as hell, while in your study you used a pretty soft brush.
One thing i've realized in my very VERY short period of studying metal is that its 40% value and 40% value edge control. I think you've got the value in this accurate enough, but the edges of the value ae just too off for it too look really metallic. I think you also ruined a lot of the described form by making the reflective details so soft, it becomes really difficult for the eye yo read it as the reflection "beeenddinngg" around the surface of the ball so you loose that spherical feeling the object has.
