The BHID isn't a modified Classic. With 3 filters (vs 2 for the Classic) and operating at 3kHz and 15kHz (vs 6.59kHz for the Classic), it probably has more in common with the DFX. But to get back to your question, I've only used my BHID as a land machine a couple of times (since I also have an IDX, CZ5, and XL-Pro) and it was pretty good. With the 3rd filter, it's more stable and deeper over moderately mineralized ground vs my IDX.
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It's a little hard to compare my Classic IDX to the BHID. At an ocean beach, the IDX in stock form was decent on dry sand, but became very unstable on wet sand. Adding the Mr Bill mods and a 12" Hot Shot coil turned it into a very good beach machine, on both dry and wet sand, with decent depth. The BHID depth is on par with the modified IDX/12" coil, but is more sensitive to deep/small gold on the beach. Plus I can wade with the BHID.
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On land, with all things being equal (stock BHID vs modded IDX with stock 9.5 coil), the BHID was more stable and deeper than the IDX. But, with only 3 lights for discrimination on the BHID vs 8 bars on the IDX, you wind up digging more junk with the BHID as junk, gold and nickels all show up on the "yellow" light. If you don't mind digging some extra junk, the BHID can be used as a land machine. Hope this helps. HH, Kevin