Wow this could be a long opinion. I think they are both great Detectors. I have owned both, but after a while I found myself leaving the DFX at home, or just to use as a backup unit. Here's why. Both machines have there place in Metal detecting. I would say 1-6 inches using the stock coil on the DFX was great. In mineralized soil, the Explorer is a better machine because it would just go deeper and virtually ignores the mineralization. The Whites DFX, tended to lose depth and become unstable in mineralized soil, even when I used the DSM program it just couldn't get good depth . The White's DFX is a lighter detector and you can swing it faster, and depending on your body strength, all day long. The MineLab Explorer is a heaver detector and your swing speed needs to be done at almost half the pace as the DFX. Taking a couple of breaks in between would be advised.
Now, at the end of the day, here's the truth. The DFX will find more surface coins!! Yes more surface coins. It will cover more area in a short period of time than the Explorer. The MineLab Explorer will find more of the old deep coins, but because your taking out more dirt out of the hole it's allot slower process. Fact!! There's no disputing this Point. It's just the facts. If you buy an Explorer you will dig deeper and find more old targets at better depths. So I recommend you get a George Leache ground shark relic T shovel, That's my digger of choice.
Listen, I'm not saying that if the Explorer search coil wasn't over the surface coins that it wouldn't hear it. That's not the case at all. I'm sure it would, without a doubt. It's just most of the time I'm moving slower, swinging slower, and I'm listening for the deep targets and ignoring most of the surface coins and trash. Yes I might loose a couple of shallow keepers in the open areas but I find more older and deep ones by doing this. On another note, I do however like to dig all targets around the tree areas, because the root's of the tree tend to stop allot of the sinking of the coins. They also tend to turn and lift coins as well.
Here is the truth. I like finding the old coins, old jewelry, and old relics etc. In some areas of the country the DFX is the choice of allot of people because there clay base is at 6 inches. Meaning there targets don't go any deeper than 6 inches in the area they are hunting. So the DFX would be there choice. If the targets go deeper say like 8-10 inches like we have here in Michigan, than The Explorer is the better choice. Again, if they hunt in mineralized soil, the Explorer is a better choice. If you were to ask this opinion on the DFX forum I'm sure you would get the opposite opinion, but this one is the truth.
Next, I will give you something else to ponder on these cold winter days. Make sure if you do get the Explorer, or the DFX, to get better set of Headphones than the stock ones that come with the Detector. The stock ones are not that good and in my opinion, and need to be upgraded but thats another subject all together. It would be like putting cheep tires on a Ferrari. Sure they work, but they just get you around and are not the performance you need. As for which ones to get, thats a personal preference. I like the Black Widows with my Explorer. They really make the deep signals sound better, thus increasing your finds. I hope this helps a little in your decision making process. Again this is just my opinion.
Tom