I am one to always agree that "if it aint broke, dont fix it". With that said, the Whites MXT is my main detector and has been for several years. The MXT is something i dont think they need to change at all....but on the flip-side the TDI needs some enhancing.
TDI is in desperate need of a 3rd tone or some type of iron discrimination...like the Minelab iron reject. I used the TDI for over a year and a half (still own it) before getting tired of the durability issues and the insane amounts of iron you have to dig. Im not "bashing" Whites, just calling it how it is. Its my favorite brand of detector and it pains me to say that the TDI was a bit rushed in my opinion. The search coils go bad WAAYY too often, the circuit boards have issues etc. Its literally a known issue with the circuit board going out.
Let me explain my gripe on IRON. Simply put, you WILL dig iron when metal detecting...its gonna happen regardless of the machine. You cant expect to never dig any of it. But, with the TDI it can get out of control. It all starts with the classification of targets (low/high conductors). Buttons come in with a nice high tone which is nice but NOT ALL buttons are high tones. On the flip side you have the low tone which consists of : Bullets, IRON, Plates, some coins, larger buttons, silver etc. You see that iron is lumped right in there in low tones with lots of good stuff, which leads you to dig so many low tones that end up being nails....it drives you insane.
If you are in a highly iron infested camp you may dig 10 nails to 1 bullet, but you may also walk right into a bullet patch and dig 10 bullets to 1 nail. Sometimes you get that "double tone" for nails which lets you avoid digging a nail but WAY to often nails sound exactly like bullets. Look at it like this, every single time you get a low tone, in the back of your mind will be this "probably a deep nail...but what if i dont dig it? and its actually a deep CS button, or ID tag, or bullet, or super deep plate etc". Thats the issue, you literally question yourself about not digging EVERYTHING. Can you handle passing up a low tone only to have your buddy swing over it 5 minutes later and dig a once in a lifetime find that you COULD have found?? Great for your buddy but no matter how happy you are for him you will kick yourself in the rear for not digging that signal!
In bad ground, VLF machines tend to make a lot of targets sound like iron due to the mineralization. In the TDI, you have a machine built for the mineralization abilities...yet because of the way they lumped the iron with the good stuff in low tones....you are almost forced to dig EVERYTHING and every nail for fear of leaving goodies behind....just like what you would do with a VLF in hot ground. Which brings me to "button mode". It happens all too often, people get frustrated with the IRON and flip it in Low Conductivity and dig button after button....while not even hearing plates, bullets or Lord knows what else.
I went to the GPX 5000 and very happy with the machine. Pricey...YES. Piece of mind knowing that im not leaving stuff behind...PRICELESS. Its incredible! If White's would have added a 3rd tone for Iron or added some disc feature for iron i would have never got a Minelab in the first place. So all in all i feel Whites is dragging their feet in the Pulse technology...