I have owned neither, so this is just my opinion. I would say that the Golden µMax is probably the better machine, but it is priced so close to the Vaquero and even the Deleon that it probably gets overlooked. I know Monte has posted some negative comments about using the Golden in mineralized soil, because of the preset GB, but I don't believe he popped the face plate off and set the GB to his soil. That's not an oversight on his part, as his comments were about the Golden out of the box. Apparently there are two adjustments in there, one to set the GB, and one to adjust the tones.
One of the few things I liked about the Sov GT was the tones. To have tone ability in a Tesoro would be great.
I intend to add one to my arsenal sometime this summer. I'd like to get a used one, but they are hard to find. Generally if one shows up for sale, it's sold within minutes. Makes you wonder if the Golden is another well kept secret?
Dan