That thing was a permanent fixture on the kitchen bench for a bout a month in winter - spent many nights poring over the platinum card fishing chips charts. Haven't had a chance to get on the water with them yet, and I'm still not convinced everything they show is there, but... if they're accurate, there are some major structures in my neck of the woods I've been missing for the last 25 years eg holes 200m deep in surrounding water of 100m, mountains a coupla miles out side the shelf that shoot up off the deep etc