I have used the WOT exclusively in the Exp I for over a year as my only coil and loved it. I have mixed use of WOT and standard coil (and SunRay 5") on my Exp II and still love it. I also use it heavily on the Sovereign (at least you can bag-hip mount the Sovereign). I can't speak for the Detech 17.5, but I see more disadvantages than advantages to the extra-large sizea as discussed in other replies. Good points on the WOT-there is no doubt in my mind that it will find more older coins than stock coil in soils not TOO junky. It will wade through a quite junky soil and still find things, but obviously the cleaner the soil the better it will perform. An OLD ballfield, picnic grove, etc with no pull tabs and few nails sings out for the WOT.. I would say it is finding some coins a few inches deeper than the stock coil, but the majority of old coins found with it (in hunted-out areas) are still mostly 6-10" (Chicago area, medium mineralization soil), similar to stock coil. What seems to be happening is that some coins, because of tilt in soil, nearness to a small piece of junk, or sheer cussedness give a weak or very mixed signal on the stock coil, perhaps shifting things well toward the iron left side of scale, and may be passed by as junk. The WOT seems to get a stronger signal back to process, and they sound more coin-like, and you dig them. Pinpointing is no more difficult than with stock coil. ANother surprise- the WOT picks up very small items, much smaller than you would expect. A half-dime or silver 3c piece is no problem , or a tiny button, .22 shell, fraternity pin and so on. Beaches or fields with coins and signals far between can be covered much faster with the WOT than stock coil. The NEGATIVES- some obvious. It is HEAVVVVY to swing. It is hard to tighten sufficiently without stripping bolt so it doesn't fold every time you lie the detector down. The detector rolls over easily when you put it down. Very junky soil becomes impossible. Depth gauge is of course off a bit. I am sure all these things hold true for either detector, but I am very happy with all the WOTs I have had, which have worked faithfully and found scads of neat things. Good luck!