Well I agree... I like to tinker with the settings as anyone who remembers me from before knows... Like to try to drop the sensitivity and get rid of any chatter and get closeup to places I should not be able to... Leaning toward the 600..I know it does not allow the amount of tinkering I want like the 800...buy just not sure the extra money for the 20/40 frequencies will be worth it for me...not going to be digging any gold nuggets out where I look...rings yes...I'm sort of thinking along the same lines as you....i'm "only" 52 lol but i swing an etrac for long beach hunting sessions and its getting a bit much.Problem is,i know how good the etrac is at the beach and i'm reluctant to give it up,i know all the reviews rave about the nox at the beach but "seeing is believing" and "better the devil you know" spring to mind lol.
I met an old guy at the beach the other day using a vanquish which isnt much lighter than the nox and it was incredible to swing.......no weight at all,so the nox is definately a tempting machine.If they have as good a performance as an se or etrac its really a no brainer.
Also extremely concerned with the coil tab issues and some have said lots of chatter...thinking they do not understand some areas due to mineralization, really require you to make adjustments despite auto ground balancing... Always had fun with the dfx trying different things once I knew the machine...
Also been looking at the AT max and F75.. but I keep reading where people keep the 600 or 800 and drop the Garrett...I saw a guy they used to run around with the F75/Fisher, said he liked it.