XL500 Work Horse
It is fairly common to find these units used because they require a commitment to learn well. BUT, they are the best I have used. For 12+ years I have used this unit, the only drawback being batteries. So I opened the case, put in a quick connect fitting, built a second ni-cad pack and bring along a field charger. Now Im never w/o power and no, it doesnt leak.
In time you will learn every gold whisper, iron burp and coin thud. You can't go wrong.