West Coast USA, East Coast USA or some other country for beach hunting? It matters.
I have used the Equinox 900 at So-Cal beaches and I thought that was one of the strong points of the 900 along with gold prospecting with it in Arizona. Both places had moderate magnetite mineralization which the 900 handled well. So I would highly recommend the 900 for mild to moderate black sand beach hunting.
It did not do well at all at sites with higher magnetite mineralization where its target IDs were very unstable on 5" or shallower targets and it falsed on manmade iron and the natural magnetite in the soil relentlessly. It was basically unusable here where I live in Colorado. I contacted Minelab and they sent me a new 900 after mine was shipped to Australia for testing. Same problem. Minelab did nothing to fix this issue, so I sold it. Got a Manticore afterwards and I have had zero issues with target ID instability and very little falsing on iron whether natural or man-made.
I have also used the Nokta Legend at So-Cal and East coast USA beaches with no issues. I used the original 11" round coil and the 9.5X5" LG24 coil. The newer 12X9" LG30 coil did not have anywhere near the depth of the original 11" coil at these beaches in testing. Legend 1 was also great in the higher magnetite mineralized dirt in my area in Colorado.
I have been field testing Legend 2 for the last month or so. It had issues with the high magnetite mineralization here but unlike Minelab, Nokta has gone out of their way to find solutions for the target ID instability and ground noise that I was experiencing due to the high mineralization. Like the 900, Legend 2 has been great on mild to moderate mineralization.
The last software update of Legend 2 fixed most of the issues I was having so now Legend 2 is superior to the Nox 900 at least where I detect. I have not had the opportunity to test Legend 2 at a saltwater beach yet.