Was out just a few days ago with both the Coiltek Gold Hawk 9” round and a NF Exceed 12” x 7”. In two days dug 154 targets using the two coils, with 17 bits of gold and most of the rest being shotgun pellets.
There were few deeper targets encountered to gauge depth performance, but there were a couple of other things that I noted.
Firstly, the Gold Hawk was better at maneuvering among the clumps of grass and stones in the area I was working due to its round shape. Whist the Exceed has a narrow transverse section which is good for poking type movements, its longer axis made it harder for normal side to side swinging in uneven or grassy terrain. Also its lighter weight also meant that grass clumps seemed to retard its movement more easily, with the result I often had to push with more pressure to keep it moving in those places.
The second reason is that the target signal on the round coil seemed more distinctive (mellower rise and fall) of a true target. The elliptical seemed to have a narrower target sound that was harder to pick from random noise or EMI events and I seemed to have to check the signal with more time and care to determine whether it was a true target signal or not.
BTW I was running the 6 in auto one.
Of those two, my vote would go to the 9" but that is a personal preference based largely on practical matters not on absolute performance measurements. Given that the number of targets I found with each was roughly proportional to the amount of time I used each, I don't think there can be much between the two.