I have the Vision which is the same thing as the V3i, they just had to change the name because of some trademark issue.
All metal is just that...it does NOT discriminate out junk like pull tabs, tin foil, iron, etc. And according to White's, without the discrimination, this setting is the deepest seeking. The various preset programs like Coin & Jewelry, coins, etc. have preset discriminating of tin foil, pull tabs, etc so the machine "sees" just the good stuff you're concentrating on.
I understand that the VX3 has less whistles to confuse you but even the big brother can be mastered fairly easy. Reading the manual is the key and start out just adjusting the easiest settings and go from there. Use the preset programs until you understand what the various sounds and readings are telling you and once you figure that out, it's all cake from there. Practice, practice, practice!
Al