I migrated over to the Deus after enjoying using the Explorer SE Pro, mainly due to the weight of the Explorer and its inability to work in heavily iron infested sites. Being so light means extended hunts without feeling fatigued at the end of the day, even swinging the 13x11" coil. The Deus would have to be one of the most flexible detectors I have used with regards to performance, discrimination and tone settings, or on the other hand it can be a simple turn on and go detector if that is your thing.
The lack of weight and fast recovery speeds allows you to cover large tracts of ground in a short amount of time, whereas previously I would be down to a crawl with the Explorer trying to weed out out masked targets - covering a lot of ground means larger coils on the Explorer, and unfortunately that also means more weight.
Using the Explorer mainly on an open screen using multitones, I found it a pretty comfortable transition over to using fulltones on the Deus, I prefer to hear everything and use my ears to do the discriminating. Fulltones would have to be one of the most informative tone setting I have used on a detector, it really does allow you to detect solely via the tones rather than relying on less accurate target ID's.
Some people gripe about the fact that the Deus runs via rechargeable lithium batteries, though I find it extremely convenient that if you forget to charge up overnight, even an hour charge next morning will give you several hours of detecting time, not to mention being able to top up when in the field during lunch break.
A lot of thought has gone into this detector, both on ergonomics, quality of manufacture and futureproofing. Pretty hard to believe it was first released way back in 2009.