Lawrenzeno,
Ive noticed you've been asking around alot regarding the V3 so I'll just give you my 2cents worth.
I have both machines, and my 1021 has been calibrated by Nasa Tom and air tests a dime around 12".
My V3i is a very deep machine (especially in boost) and I would say its just as deep as the 3D. I have dug just as many deep coins with the V3 as I have the 3D. I have many hours on both, more on the V3. To compare the 2 is difficult at best because they are 2 very different machines. I love the 3D for its power, simplicity and the ability to id old coins in hi-tone.
However IMHO, the V3i cannot be beaten by ANY detector for jewelry hunting simply because of the amount of information it gives, especially in the analyze mode, and you will dig FAR less junk. The 3D cannot id a screwtop from a coin, the V3 does not have a problem with it because in analyze mode the top line of the hump is always blue signifying the 22.5 frequency. Coins are always green (2.5). except the nickel which is the blue 22.5. And speaking of nickels...the only time Im ever fooled over nickels with the V3 is over can slaw and very few other peices of aluminum.
There are many, many tricks to be learned with this machine and and probably will be a few more years till it is more fully appreciated.
I know this was alittle more than you asked for however I noticed you were also asking about screwtops and ect in other posts.
Hope this helps.
Aaron