"calabash", and again, I learn much from your videos, when I see another video posted by "calabash", I'm drawn to it like a magnet. Having said that, I think 99% of MY hunting would be in Multi, since I am more a "coin & jewelry" guy. Terry Soloman speaks highly of the 600, which speaks volumes about how good the 600 is. Just what might be the advantage if any, in going single Freq. of 20 or 40 with the 800. Of course I understand there are "extras" on the 800, but other than electronic "prospecting", what might the 800 offer over the 6 in coins, jewelry and relic hunting. This is a small question, but the point is that I DO value YOUR opinion. As far as the word "obsolete"? I can only speak for machines that I use, those being the AT Pro, and the Minelab X-Terra 70 and Safari, and I believe that word obsolete might very well apply. Thanks for taking the time and effort in the making of these really "informative" videos. Well done.