The first mass produced BFO detectors actually were great fun to use and the fact being ,your comparing the latest up to date detectors to them Keith ,but we were not,and the reason we wern`t was, we had nothing to compare them to, so we thought they were absolutely great.
If my memory serves me well, I think on average they had around a two inch depth on coin sized objects and obviously bigger Iron objects would be found deeper .They were exactly what we could only dream about having in our possession ....a real `live `working metal detector . You have to realize , a metal detector was something we had only dreamed of owning from first seeing them initially for sale in the cube boxes or rectangular boxes on the back page of the Marvel or DC comics from the USA from the ACME range of products along with X ray glasses and other wonderful things to buy, you couldn`t buy over here.
Then all of a sudden they were here . The fact they had no discrimination was neither here nor there because, Discrimination !! what was that ? We didn`t know what discrimination was, because even then it hadn`t been incorporated onto a detector , so we didn`t crave then what we hadn`t been invented then.
The fact was, that it was a metal detector, that actually found metal things ,and nothing could take that away from us.It was a dream that had actually turned into a reality.