Love to.
Ok, lets compare the competition.
First, there is the Dual Field by Whites. Decent PI detector and the weight is about right. Problems: if you want to adjust the volume, you have to open the unit and considering that you need to factor in wind noise, surf noise and beachgoer noise which varies every time you hunt, opening the unit at the beach to adjust the volume poses some serious concerns (like not closing it correctly). Also, the 12" behemoth coil floats like a cork, so you either need to weigh it down in the water or apply enough constant pressure to keep the coil at the bottom. Pinpointing is difficult and after awhile you feel like you're swinging a garbage can lid. It got old for me. Some folks don't mind it, I do.
Next, there is the Garrett Sea Hunter. Good PI unit, built like a tank. Weighs over 5 lbs though, so you definitely need to hip mount it. Certain features I think are ridiculous, like the discrimination knob. PI detectors have no discrimination. This seems like a bad marketing idea that Garrett ought to abandon. Be warned, if you use this knob, you will lose some serious depth. However, if you ignore the discrimination knob, this is probably the best PI detector behind the Sand Shark for the price and I believe you can still interchange coils.
Next is the Garrett Infinium. I have not bought or used this unit for the simple reason that the coil and headphones that come standard are not meant for salt water use. You have to buy another coil and the waterproof headphones a la carte. It makes the cost of the unit way too high and I wish Garrett would offer one for sale with a salt water configuration. Until they do, I would not consider the Infinium for the beach.
Lastly comes the Detectorpro PI. I used to like this unit as it was very lightweight. It functioned well but sucked the batteries dry after about 8 hours. I have since backed away from it because of routine problems with the unit that requires regular servicing that does not always seem to fix the problem. You can check the threads, but Detectorpro seems to be having quality control problems at the moment. It's a shame, because I really like the idea of this unit.
This leaves the Sand Shark. The minuses? It still weighs in at over four pounds, so hip mounting is preferred for extended use. You have to open the unit to change the batteries (but thats true with all of them) and it is not as simple as it could be (Garret Sea Hunter wins this category for easy battery change). The Sand Shark used to be available with interchangeable coils (8" or 10.5"), but since they have been reintroduced, the coil is hardwired to the unit, so you have to choose one or the other. That's it. The minuses are minor ones. The pluses? Exterior volume control which comes in very handy. Excellent depth, so buy a good sand scoop. The unit is backed by a lifetime warranty unlike any of the other units. You can adjust the settings for your sand conditions better than just about any other unit I have worked with. It is solidly built.
As to which coil to get, I recommend the 8". Pinpointing is easier, covers plenty of ground, and you will get the all the depth you'll ever need. Some prefer the 10.5" though, so it just a matter of personal preference.
Hope all that helped!
