I havent owend a metal detector scince about 15-20 years ago. and it was a radio shack cheepy. im considering buying a vaquero, after doing some research. how much better is it than a silver umax or a cibola? as far as sensitivty and depth. im going to just be looking for pretty much any thing I can find, hopefully silver coins, jewelery .... etc. if there is not a huge advantage then maybe Ill get one of the cheaper ones. and also where can i do a little reading on how to operate these things besides the manual. The way i remember it is set the sensitivty and the ground and the thing would humm when it went over metal. I read where you listen to different tones for different metals?