Not sure if you have tried it or not but test without the zerolemon case on. I have it for my S3 and it doesn't work with the case so I am thinking of cutting a hole where the sweetspot is.
Got my ring yesterday. The lovely sleek looking 'stealth bomber' version.
I have a Samsung Galaxy S3 with the ZeroLemon Battery and Case. The ring works without the case but not with the case. I am considering making a cut out on the case where the sweetspot is and seeing if that makes it a bit smoother.
On a side note the ring looks brilliant however I wore it for an hour and started to notice scratches and marks already on the metal. Baring in mind I sat at my desk for the hour typing and using a mouse I was rather disappointed in this. Maybe I am being 'over sensative'?
Either way it seems to work ok :)