Useful perhaps, but certainly not comprehensive or even unbaised since it appears that site leads to only one conclusion - Buy the treasure mate.
Which might be well founded I dont know, having never used one.
If your not inclined to spend in the 3 digits for a very useful but basically simple tool, have a look at this
http://www.billsdetectorsales.com/pinpointers.html [its the one shaped like a gun].
Has audio/vibrating/visual alert, adjustable sensitivity, and a useful detection range of say a quarter sized object from about half an inch to over an inch.
And the below $50 price tag cannot be beat.
Not trying to ruin any sales here, but this forum is all about info and options, and this is certainly an option in my book.
Have used it for over a year with nothing but great results - And I would really have to see vast improvements and features to consider spending 4 X that amount on something else.
Just keep in mind that, whichever one you chose, they are all fairly delicate instruments and do not take the abuse typically associated with retrieving objects out of the groud very well.
Nothing like getting a buzz and think you are over the object, only to get a second quick buzz indicating it is now off. Threw me off the first few times but then I got used to it.
