Background: I'd used the earlier Explorer models (borrowed), so was familiar with the tones and 'software'. Otherwise learning curve would have been lengthy. I also used a Minelab Sovereign for many years. Others have more experience than I with the SE, and maybe they can add to what I've said.
Plusses - better balanced than previous models; MUCH more user-friendly, and faster responding.
It will go deep - in saltwater/mineralized sand, which can be a bugaboo for some detectors, I got a gold ring at 10", and an Indian at 8+.
Negatives - very poor screen visibility, even with CONTRAST at max. setting; (I don't want to put on the backlight, as battery drain will accelerate); today I tried a Full Screen (enlarged) display, and it helped some. Still getting used to the sounds, which for this series is the biggest challenge, I think. More complex than the Sovereign. And there are several choices for what you want your targets to sound like, to complicate matters.
After ~40 hours of use, I'm comfortable/confident with the SE for about 80% of the time. I'm still learning and the guys on these forums have helped me a lot.
I like the SE a lot - I've been testing it on hammered (by me and others) sites, and am impressed. It wouldn't be my first choice for 'prospecting' large areas with few targets, like farmfields, woods, and winter beaches - too slow, I'd use the Sovereign with the WOT coil. But for old 'cleaned-out' sites where I like taking my time, it will be my #1 choice. And also for certain saltwater areas, where deep targets may be available in the rocks (where I wouldn't use my pulse machine - too much 'blind' digging). Good luck!