The advantage of the 800 over the 600 is that the 800 can use the 20Khz and 40Khz as single frequencies. The 600 only uses those high frequencies in Multi frequency, in a still unknown weighted mix. That mix changes depending on which mode you choose. The 600 doesn't have the gold modes, but, in Field 2 you should still be able to find a fairly small gold item. Maybe not tiny nuggets that the 800 can find, but, small jewelry should still be findable.
800 has higher settings for recovery (7 and 8)so should work better in heavy metal areas, 600 has max setting of 3 that is equivalent to 6 on the 800. The 600 recovery settings are multiplied by 2 to match the 800. So essentially the equinox 800 should go deeper due to the number 1 recovery setting, I noticed a possible 1/2” difference on an air test. Although I could only see this setting for confirmation of a faint signal from a different recovery setting.
800 has gold modes and extra single frequencies 20 and 40khtz
800 has user mode / button for quick confirmation at another setting….. not as helpful as it sounds as requires two hands to operate. But still useful.
600 has courser settings for recovery and iron bias. 800 can be finer tuned to conditions but average detecting would never notice. The 600 settings are multiplied 2 for recovery and by 3 for the bias settings to match the 800.
Equinox 800 can change all tones and tone volumes. The 600 can only change the lowest section tone and volume. Does not matter in 50 tone but in 2 tone I find 20 annoying and would prefer 15 as the only high tone.