To answer your question, I believe either would do fine as defined within your desire. In fact, almost any rig out there will do fine for rings...the good thing about the AtPro is it hits gold chains that are invisible to most other rigs...I dont know about the Gold, but a fellow can assume it does too....thing is, most of your targets in those kind of modern areas are going to be shallow, like 3" to surface, and theres a lot of foil and scrap, so you dont need to or want to run with too hot a sens...its more of a strategic hunting style pertaining to the age and layout of the place, coverage, and then a numbers game than depth..
A guy has to try to recognize the right signals and right areas to hunt depending what the junk and travel patterns are saying to you...put in your mind you are most likely going to find a 2gr 10 k womans ring, but also do not discount a nice 14k Mens figaro style chain, down in the grass roots... especially if the field is open to the public and you have the right gold wearing clientele using it...
I have extreme confidence in the Pro for gold rings or chains...I have never run an AtGold...I think in this instance you are more hunting 'People that wear gold' than the 'gold item' itself...at least thats what I've found...I'd set up light and tight and work a likely area for old glory hunting for a nice heavy chain, 15gr and up...On the Pro, that would be running in Pro Zero, Iron off, 40 disc, and 3-5 clicks down from full sens, depending on how deep the grass is and how high I want to fly the coil off the deck.....no worries on ever missing a ring, they hit so hard...'course so do tabs...
...The trash/depth/clad you find will tell you the age of your site and your odds off success for gold in about 5 minutes..
Mud