I'm thinking about buying a Lowrance H2O. For you guys that have used them: Are they any good for showing bottom detail, ledges, shoals, etc? If yes, is that with the pre-loaded map software, or would I need to spring for one of the packages like "Fishing Hot Spots" maps? An extra $100. I'm going to be fishing as a co-angler a lot this year and was thinking I could bring it to tournaments.