My guess is your answer would be to find things. I think that is why those who stick with the hobby for very long end up with an Explorer. A very simplistic answer is that the Explorer is good at making great finds.
Of course, the DFX is very capable also, as are other great detectors out there now. No matter what you use in order to make great finds, you first have to pass your coil over the top of it. In other words, you play a big role in whether you find things or not. There are other things that come into play like how mineralized is the ground where you hunt, what you are hunting for, and how patient and determined an effort you have time to give to the hobby.
When everything else is in place then it comes down to the performance of the machine. The Explorer performs very well in almost any environment. It detects deep and IDs accurately. It handles minieralized ground well.
Is it perfect? No. None of them are. It is a detector that you can work with and usually find whatever is in the ground as well and usually better than most.
Hope that helps.
HH Alton