Does it have to be new? Have you considered a used Excalibur? I'm not familiar with the differences, but for an in-the-water, especially saltwater, detector, the Excalibur is hard to beat. I own a PI pro but several my md'ing buddies have the dual coil and love it - except for the coil weight - which is not a problem if you're using it in the water. Of course, if you want to really reach down a get the gold with an Excalibur, you'll probably opt for a WOT coil sooner or later - and they are heavy, too (need that swingy thing!)
Until you've used a pulse machine for a long, long time, though, digging hair pins and iron nails seems to take most of your time. Even though the characteristic "dual beep" on iron targets eliminates a lot of junk, I still get fooled enough to understand your dislike of a pulse machine (I'm assuming your dislike stems from the lack of discrimination with a pulse induction machine) and I'm always wondering if the double beep wasn't two gold rings lying side by side
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I understand that the White's TDI is a pulse machine with some discrimination capability but have never used one. Of course, the TDI is not a submersible machine. I do own a Eric Foster Deepstar pulse machine which I believe to be a predecessor to the TDI in as much as pulse repetition rate, pulse width, and amplitude are configurable so there is some discrimination capability. Unfortunately, that machine runs at 14.4 volts and is a heavy current user - The battery pack consists of a NICAD bundle of 12 C cells (that IS heavy).
By the way, you should be able to get a good price for your Whites dual field - most guys that have them say they are very good machines and are still much in demand - that should bring that $1200 price tag on the Excal 2 down to a reasonable sum.