Thinking of purchasing a 540 or a Double Score. At 74 years young I am looking for a excellent detector which is not to difficult to master. I'm a dirt hunter with over 30 years of off and on detecting. I had a 540 once and did very well with it. This new Double Score has a few extra features the 540 lacks BUT will it out perform it? I do have a Nox 700 right now and plan on keeping it. I hear the Legend is a great detector but have no interest in learning a new machine with that many adjustments. Looking for your thoughts on these two. Thanks