Crevias,
Has the MXT been an upgrade? yes and no. Depthwise, even digging the wispers, I haven't dug as deep with the explorer so in this respect it was not an upgrade. In regards to recovery speed, trash separation and sensitivity to small items, yes it has been an upgrade. Hunting the same locations that I did with the explorer, I am pulling out items I missed that were close to trash and I have started to find a lot of earrings missed by the explorer. So, overall for my type of hunting it has been an upgrade. If I had the money would I own both, yes. But next on my list is a waterproof detector and then eventually I wouldn't mind picking up an explorer xs or ii to have as a backup for when I do go looking for the older coins.
For your style of metal detecting, this may not seem like an upgrade, which is fine. For you the explorer is the way to go. As I mentioned before, I know the explorer is a good performer for many situations. I have since discovered, that there are certain situations where a less expensive metal detector does outshine the explorer. Since that niche of metal detecting is where my interests are, it makes logically sense for me to now stick with the MXT as my primary unit. This, of course, is my personal opinion. Feel free to disagree.