I help friends of mine who have purchased an Equinox after using another brand for a long time. To say that most of them are overwhelmed with all of the Equinox features would be an understatement and these folks have been detecting for years. The people that have adjusted well to the Equinox were former Minelab X-Terra users or those that do not mind multiple tone operation. So, if you keep your sensitivity levels lower than the default levels and just use Park 1 multi frequency in 5 tones or less for awhile in easy to detect areas, the Equinox 800 can be a turn on and go detector. So can the Equinox 600 for $250 less. So can the Vanquish 540 Pro pack which is $150 less than the Equinox 600. I have used them all and still own the Nox 800, 600 and a Vanquish 340. To me the Nox 600 is well worth the price difference over the Vanquish 540 IF you want to do some serious metal detecting and if you want or need to detect in situations where you might accidentally or on purpose submerge your detector or you have weird or high mineralization and you need to manually or frequently ground balance your detector.
If a new user decides to crank up the sensitivity on the Equinox, it will pick up every metal target in the first 11" or so of the ground including tiny 1/8" sized pieces of foil, can slaw, iron fragments, tin fragments, I mean stuff that your pinpointer won't even hit. Lots of new users have complained about disappearing targets and EMI problems and this is one reason why. The Nox 800 and the Nox 600 are extremely high gain detectors. The Vanquish series use a detecting mode taken from the Equinox that is much more benign and will not drive a new user crazy.
Otherwise, the Vanquish 540 is a very good quality simultaneous multi frequency detector with several nice bells and whistles like wireless audio, backlight, excellent discrimination patterns, salt water beach capabilities, good recovery speed, user software updatable online, good coils, very light weight and easy to adjust for anyone of any age, and most of all it can really detect accurately on low, mid and high conductor targets even at the edge of detection range, and you get good, no nonsense service and a three year warranty.
The Equinox 600 has all of the features of the Vanquish 540 and many, many more. The 800 takes the 600's features and expands on them even more. To me, the 600 and 800, if you like them and they suite your detecting needs, are forever detectors, if there is such a thing. The Vanquish series are stepping stone detectors for those who might want something better later, for those who just want to detect a bit, for those who need lightweight adjustability (at my age sometimes I do for sure...) or for those who just want to go out and have some fun. You can do that with the Equinox too but on the other hand, the Equinox is one heck of a detector and if you want to go into the details and get really serious (addicted is more like it) that is easy to do with the Equinox.