The value of trading up from a the VX3 to the V3i is dependent entirely on you. The VX3 has essentially the same engine as the V3i, with fewer controls for those who do not wish to invest the time it takes to understand the V3i in order to use it at (or near) it's full potential.
Are you willing to put in the time and effort it requires to study the books and swing the coil? Will you take the time to study and learn how each of the settings relates to all the other settings and how they affect the detector's performance?
If you would rather just ground balance and go, then the V3i really isn't for you. That's not a bad thing. The bad thing would be investing money in a detector, but getting discouraged because you see an actual loss in performance, rather than the amazing gains the advertising indicates.
