right now i am using a "cheapy" Eagle cuda 168 on my boat. http://www.eaglegps.com/Products/Sonar/Cuda168.htm . i mostly fish the Great Miami river in Ohio so i figured i didnt need anything special to do the job, but i have been reading and hearing comments on the cheaper models saying they arent very good at marking fish near the bottom. is this true? i rarely ever use my sonar to locate fish, rather i use it to see drops, snags, and locating the main channel, but it would be nice to see the fish i have been missing if that has been the case. was looking at this one at Gander Mountain yesterday... http://www.eaglegps.com/Products/Sonar/FishMark320.htm it seemed a really good deal for $149 but i would like to hear from the "experts" before i go buying a depthfinder i may not need.