Tough call, the 5 will pick off a few things others have a hard time locking in on, especially in extreme iron more than non ferrous trash.. the X8 does a great job at getting most stuff in most situaions.. Like Nimrod I usually use the X5 as a finishing coil or getting in to tight spot between trees/rocks under brush etc.. my problem is I get a bit anxious for signals and start going too fast trying to cover more ground when I use it.. If I were to only have one I would say the X8 as a happy medium.. The Joey also seems to do well in the high trash without quite the depth loss and good ground coverage at the same time.. However while it seems more sensitive to the smallest targets(tiny rivets,22 short sized targets) than the X8(X5 seems just as sensitive to the small targets as the joey), the Joey is also a bit more unstable, falses way more in wet conditions and hits a lot harder on hot rocks and iron.. I find the Joey requires a much slower sweep speed for the smoothest operation, but it does seem to see some stuff others may have missed, and the shape allows for hunting some tight spots.. the ML 8 inch also seems to have a slight edge on sensitivity to small targets and perhaps a bit better in high iron than the X8, but its also heavier and harder to keep in postion, without any depth advantage.. My coil of choice remains the X8, but I do use all the others more than I do the stock coil.. even though I think the Stock coil the deepest of all on land and is pretty good at seperating in trash, just a bit too big for most of my sites and heavier.. I use the stock coil at sites I know has the deeper targets, and are fairly open.. The X8 will get them down to the 10-11 inch mark which is plenty deep for the majority of sites.. I suppose the WOT will get the deepest, but I just dont have many inland sites I can use it, and for land hunting it seems to require a much lower sensitivity setting for smooth operation, but for a big coil it does have very good sensitivity to small targets. If you get it in high trash forget it.. you will hear things off the edges and get multiple tones consitantly... At any rate I probably got you more confused with my answer then you were before, but as you can see there are uses for all the coils.. my personal choice over all just happens to be the X8, mainly because of weight and smoothest operation.. my next choice would be the X5, then Joey. I think those would cover most every need, unless you have sites that are open and fairly clean or beach hunt, then you might want a WOT.. the ML 8 inch may be subsituted for the X8, but it is almost as heavy as the stock coil and covers a bit less ground then the X8, but then again is a bit cheaper.. I dont think that either does much the other cant and its more of a coverage and weight factor to me..