for me,the Excaliber has a short learning curve.I like to use it in pinpoint mode.The difference in sounds and the depth are very noticeable and easy to distinguish.It will discriminate all iron if you want it to,but I like iron and prefer to look at it.Where I dive is very trashy also and what I like to do is go for objects close to the surface.The Excaliber has the best depth of any underwater machine I have used,but that ain't allways a good thing,It takes time and air to work a deep hole.Another spot I hunt has no trash and deep stuff as well,but I don't go for it unless it sounds real good.I have had no problem with my 2 Excalibers,1 is 5 years old,so I don't know about service,but I called a couple of times to ask about a modification I wanted to do and talked to a guy named Gus,very nice fellow.Oh yeah,the knobs are crappy,they go past the marks and the yellow inserts fall out,but it doesn't affect anything,just irritetes you.