Separation wise and depth the ultimate 9" is very similar to the stock viper. I think the ultimate handles iron wrap much better and reveals coin spills better than the Garrett coils.
I like the round coil for one main reason, for woods hunting it is robust and the round coil is just easier to work around undergrowth.
Other than that I don't think it's worth the money they charge. If you are in high mineralization and high trash areas your better off buying the smallest coil first.
Apex found me quite a bit of $$$$ so it owes me nothing. I even have a Steve G mid and lower carbon shaft on it so it is very easy to swing all day, slightly over 2lb mark with the 9" coil.
I suppose Garrett intended it to be an upgrade for the Ace users but really missed the boat with the limted audio option. The could have easily added pro audio and left the door open for fully waterproof machines down the road to compliment the AT line.
So many companies just miss the boat on this stuff, drives ya crazy..