To answer as honest as possible, I can give an answer based only on the machines I have used.
For gathering screaming silver signals,, I really like the Etrac. However, the Etrac doesn't get along with rain, or water, in general. That situation would in the past, have me reaching for the AT PRO. It is submersible to 10 feet but is most effective in fresh water. Another Minelab machine that I use when the hunt is in salt water, is the Excalibur. It is THE Salt Water machine if you are going to hunt Atlantic or Pacific Beaches. (Submersible to 200 feet.) Since I have sold my AT PRO, I have the luxury of selecting the CTX 3030 as the machine of choice for the day, in the event of precipitation or when hunting in an area that is known to have given up deep silver.
Another machine in the arsenal that can hunt in multiple frequencies, is super light weight, and can give you 18 different programs to select from, is the DEUS. However. I believe it is most effective in open farm fields or the woods. I don't believe the French Designers had NYC Parks in mind when they were thinking where this machine can be most effective.
Recently. While hunting in the woods with the Etrac, I was reminded of the beauty of the wireless headphone feature that the DEUS has to offer. My Etrac headphone cable got snagged a few times..
So there you have it. Select the machine according to the conditions and environment you will face during the hunt. IMHO