I can not comment reliably re your USA beaches because I do not know the mineralisation involved. (I am in Australia).
Remember that this detector (SDC 2300) has been designed to very portable, and locate gram to sub gram gold at shallow to medium depth in iron mineralised gold field conditions and it is very good at that task.
The SDC 2300 is an expensive metal detector and could be a bit of an overkill for beach work, but maybe like myself once you have tried one at the beach you will probably put your other detectors in the closet.
If you have a Gold Bug Pro with an 11 inch DD coil then this detector will find almost everything that the 2300 can find in normal salt beaches. I used one of these detectors for a while and it literally replaced my Infinium over the wet and dry sand. The Infinium was then used for in water detecting until the GB was stolen from my car.
The SDC 2300 is fairly new to me but it has proven to be very good over normal salt beaches with exceptional sensitivity to small gold chains.
The detector has a Normal Mode & a Salt Mode with several sensitivity settings in each mode.
In the Normal mode the detector will generate some ground noise from the wet salty sand, dry is fine. In the Salt mode at max sensitivity, ground noise is near on non existent and the detector has very good sensitivity and depth capability for coins rings and chains likely to be found on beaches.
I think that if your beaches contain a significant amount of iron mineral plus salt then you may have to tolerate some ground noise which is what happens on some of our dry salt lakes in the Western Australian gold fields.
Like most PI metal detectors the 2300 likes iron and will find steel bottle caps at two foot depth in wet or dry sand. Small coins like our 5 cent piece were detected at near on 18 inches at max sensitivity in the salt Mode.
If you are a dig everything detectorist then you will like the 2300. It will not miss very much at the beach or in the gold fields but remember one thing. It is not a depth monster on large gold from 10 oz upwards. The GPX 4500, 5000 and the GPZ 7000 will go deeper, due mainly to the fact that the SDC2300 has just one coil, an 8 inch and this limits the depth.
My 2300 was purchased second hand and at a very nice price. I would not have paid full RTL for this detector if I was only going to use it at the beach.
The detector is much more sensitive to small gold items than The Infinium, Sand Shark, Dual Field, Safari, Excal The Sov and other BBs and FBS metal detectors.
Hope this is of some help to you. These are my opinions of the SDC2300. I am sure that others may have differing opinions re this detector.