Bream beds can be tricky if not in deeper open water, what I mean is it some units can blur them out. Its hard to get a good image right up along an uneven shoreline. You want the most detailed unit that you can afford. Humminbirds new helix g3 units are the ticket for a lot of people, the new helix 7 g3 has mega imaging which is VERY detailed. I would not suggest any smaller than 7". One step below the helix mega g3 would be about every other unit, old helix g1/g2, core unit humminbird (800, 900, 1000 series), garmin 73/93, lowrance elite ti.