Long time Tesoro users have their ears trained to where those nuances are now part of their ability to determine targets and it gives them another 'weapon' in their hunting process.
Not only that, but every ones ears and hearing are different. The type of headphones used also has to be factored in. I have found a lot of analog units can be made better or worse, just by what headphones you use.
Having used several Tesoros in the past, and still have a Mojave in the stable, as well as a DeepTech Vista Gold Gain (VGG), I can say that the analog features and the audio of the VVG is very similar to a Tesoro. More so than compared to any other unit out there (digital or analog).
Hard to explain, but when using a Tesoro or VGG, with good headphones, there is a lot of audio nuances that can help in identifying a target. The edges of targets and they way they sound when the audio ends ( the 'pfft' sound or how it is not completely 'clean'), tells a lot about the target. Being a tone hunter for the most part, having audio nuances where a target just stops you in your tracks via the sound and how you can then focus on the target and sweep the coil and get more info just by the audio is so cool.
Bottom line...if one is thinking about a DeepTech unit, and if it can be similar to a Tesoro in terms of audio and how it reacts to iron vs non-ferrous targets, you won't be disappointed. The main thing is, you will have to use the DeepTech unit for awhile to start getting the ability to hear those nuances. Just like it probably takes a bit of time when first using a Tesoro. But once the 'light bulb' goes on and you start to mesh with the unit and the way the audio reacts over targets, it will be just like hunting with a Tesoro.
The audio nuances are there. The analog sound is there. Some DeepTech units have iron break and the ability to set the volume on iron. That is a big plus in my book.
My opinion....getting a DeepTech unit and the one that most looks like it would compliment whatever Tesoro unit you have, will be a good choice. Just be aware that some of the control boxes on the DeepTech units are bigger, and although they weigh a bit more, they are still balanced very well (think Tejon in terms of how some of the DeepTech units are built...battery box under the arm cuff). I can hunt all day with my VGG with either the 11 inch or Super Six coil with no issues. And they go DEEP and have super fast recovery speed. Relic hunting or dry sand hunting for gold jewelry is a no brainer for the VGG. Coin hunting...there are probably better DeepTech units for that.
Shame Tesoro may be closing up shop. The quality of their units, price point, the service and the warranty were always good selling points.
Long live the analog units ! As Joe Walsh sings it...I'm an analog man.