If your main interest is silver wouldn't the 600 be a good choice for yards, parks and overgrown area's? It still has 20 & 40 kHz in multi-IQ according to this statement below the frequency graph on their site. "20 kHz and 40 kHz are not available as single operating frequencies in EQUINOX 600. The Multi-IQ frequency range shown applies to both EQUINOX 600 and 800." I don't see a big gain for the 800 unless you do beaches and maybe nugget hunting. I know it's to early for this but that quote got me thinking, sorry!