Not sure the reason why but the TRX probe does not seem to be a very popular one,when they 1st became available here in the UK a few folks bought them as they latest must have accessory but after a short time duration off loaded them very quickly,of course they wont give a reason for selling them in the adverts as they dont want to risk loosing a sale,The Garrett original and the newer AT versions still hold the volume sales crown,but saying that some of the Bulgarian models do offer good value but what puts me off these Bulgarian made machines is that although they offer a 12/24 monthy warranty its the long term reliabilty that i look out for and i am afraid that that the Garratt version that i use still works after all these years and never this far missed a beat.I also have a Whites BullEye as a back up probe that i carry,that still works fine and dandy was my everyday probe till the PP came along.
If my current probe packed up then i am pretty certain it would be replaced again with a original Pro Pointer just because the current on is so reliable,of course what works for one detectorist may not work for another,its all about personal choice and i also think brand loyalty pays a big part as well ie if you had a Ford just after passing your test in theory you tend to stick with the Ford brand.