Being an avid Tesoro fan who has every current model made in the current line up, so ordinarily just on the warranty alone I would say go with the Tesoro. The Cortez shares the same circuity as the Deleon so to me it is the same detector less a couple of minor things like notch and auto all metal tracking lilk the Lobo Super Trek. Based on that and the type of hunting you are wanting to do I would have to abandon my favor and say go with the Fisher CZ3D because is has the old coin mode that was specifically incorporated for really old sites to find really old coins, but watch out for the iron nails because it dines on them with enthusiasm and as with other machines you have to learn the different tones to be really successful and ignore what you don't want, so practice, practice and learn the machine. I've been in the hobby for 30+ years, so while an educated opinion it's just mine, others may differ, that's why we have forums.
Good luck!