Sure have! I've used the ATGold and ATPro well enough to say it is a fantastic dry sand machine. At the ocean beaches here in NE-Florida, the stock coil in dry sand averages a solid 6-9 and may go deeper if there isn't a lot of black sand (mineral deposits). Slap on a bigger coil and you can gain more depth as well as cover bigger areas in less time.
The wet sand in the water are the challenge because salt is conductive. In order to use the machine in those conditions, you have to decrease the sensitivity and ground balance as often as every few steps. The decrease in sensitivity will lose depth and ability to recognize smaller mass targets such as thin rings, chains, earrings, etc.