pretty dog gone good md these classics are at the least consistent I can't speak for a idx but for the classic 3 sl once learned the unit is hard to fault even round a power line . got one bout 75 yards from my home I'll hunt almost to the base no problem . I just want to try a diff digital md myself but a classic 3 sl will always be with me. hope that was a little help. I use mine on the beach wet or dry with very little loss of sen.