Hds12 by far easier graph to manipulate. Humminbird is also a winner. But I would get a helix 12 since it's closer to the hds12 in price.
The Lowrance is easier to manipulate if you are familiar with the Lowrance menus. They are a nightmare for those that have no marine electronics experience and the Humminbird is easier to learn from the start.
Humminbird Helix 12 SI, 1198c SI, 1198c SI, ONIX 10 SI NT, 360, RC-1