I recently got back into MD'ing and got myself a used White's IDX Pro, which has been working good for me. The wife wanted a detector of her own and I found a nearly new Prizm III which I got her. I checked out the Prizm III and like it a lot. It has a depth indicator which the IDX does not. I did not feel the added features of the IV and V were necessary for our needs.
The IDX already has the 9.5 inch coil. The Prizm III's standard coil is 8 inches. The smaller coil may actually be an advantage in trashy areas but I haven't really run into that yet.
A friend of mine has had a DFX for a while, which we borrowed for several days when we went on a trip. I found the DFX to be a bit too much to deal with right now, and besides seemed heavier and clumsier to swing. But I found some stuff with it and that's what made me want to get my own unit, and then later the Prizm for the wife.
The IDX is pretty good on weight and balance, but the Prizm is really nice and light (I have recurring elbow problems).
Hope this helps. Both the IDX and the Prizm III have been successfully grabbing coins and trinkets from local parks. We may upgrade later on, but for now these detectors work well enough to keep our interest in detecting alive.
- Bill