There is great deal of depth difference in any detector. "Depth" is a relative term and there are many variables. Our manufacturers, Tesoro included, do all they can to ensure they offer the latest technology avialable. More than anything, it depends on you and your experience, and how well you know your model of detector. We all know someone who uses an "antique" detector - and who beats the pants off the rest of us!
In general, you should spend a minimum of 30 hours with any new unit before you begin to make assessments. I always suggest you take the batteries out of any other detectors you may own and use only your new one during this learning period.
To your question, YES, there are differences in models. The Tejon and the Vaquero are gonna be deeper than say, a Compadre or Silver. They have more sensitive circuitry and can be fine tuned to the nth degree. Thay also can be way more erratic and darned near unusable if improperly adjuated.
Additionally the electro-physics of the thing has an impact. Getting more than the mean average of depth from the emitted field (coil dimension X .707) requires amplification that can again, cause difficulties for the unknowing.
Then there is the "detection cone" effect. Down in the depths, the practical field of detection narrows, so that any one target has less than a few square inches of excitation area to be detected in. Think about your own finds: I'll wager most of them are in under one foot, regardless, and more often that not, less than 6-8 inches. These things are just The Way It Is.
What you will find with the Tesoro line, at least in my experience, is a detector that runs smooth, is user friendly and simple to operate and has all the power currently available from modern electronics. Bells and whistles, however, are not the strong suit of Tesoro models. Usable power IS. Couple that power with a modicum of knowledge and willing knees - then dig! You wont be dissapointed.

Vance and James Gifford have done an admirable job moving forward from Jacks, (their father) beginnings. They are in their 25th year of operation and still offer the only LIFETIME GUARANTEE on their products that I am aware of.

At the very least, you will always be able to sell your Tesoro at fair prices if you are not a good fit for the model you select.
Go For It and Committ. All knowledge stems from this simple credo.
