I'll answer this for you! (By the way, kudos and good luck on the ring return)
I went from the Ace250 to the AT_Pro, and then to the Equinox 800. And I will NEVER go back!
Trust me, I loved the Garrett detectors. They're really great, solid machines. But when I took out the Equinox and returned to all the places I'd "hunted out" with the AT-Pro, my 3rd signal (very first time out!) was a large cent about 10 inches down, in a spot I must've swung the coil over a hundred times.
The Nox is noisy compared to the Garrett, so be prepared to listen to thousands of different beeps. But that's because it can pick up multiple signals *really* well. It finds coins next to nails and trash ALL the time. You'll be listening to the detector much more than you'll be looking at the display, especially when you're cherry-picking those sweet little high tones out among all the lower ones.
Also, the 'Nox comes with wireless headphones. Once you've worn wireless headphones you'll NEVER go back to struggling with wired headphones again. I still have nightmares of my shovel getting caught up in that thick, curly cord coming down off my AT-Pro headset. That all ended when I bought the 'Nox.
The 'Nox is so much lighter, too. Damn, I sound like a salesman!

Anyway, I recommend it. It'll take a few hours to get used to the sounds and signals, but you'll be finding better, deeper stuff right out of the box.