I've used the 350 for some time now and it is a good machine. It will probably take you a good 10-20 hours before you really start getting the knack of it. I would suggest turning down the sensitivity a notch or two. This depends on several factors: are you hunting in a real trashy area, type of soil, etc. If you are hunting public parks and you are finding alot of tabs you can always discriminate out the tabs but then you are leaving out some of the gold targets. I usually hunt in relice mode or disc against iron only. I've used it enough to know if it is a pop tab, most of the time. Keep an eye and ear out for the signal given as you sweep across the target. As the target gets toward the front of the coil (this is how I pinpoint) it will usually change to a coin signal, but only for about an inch or less. I then can usually say its a pop top.
Hope this made some sense.