I've owned both garmins and lowrance. You cant go wrong with either. Eagle is made by lowrance so you should'nt go wrong there if thats what you decide. I have never had any problem with a single frequency unit in the salt and I fish it exclusively. The 50 khz is supposed to help you read deeper but my 240 has no problem reading the bottom to 700' with a 20 degree transducer,which is way deeper than most people fish here in the sound. Hell I very seldom fish bottom deeper than 150' unless I'm after bottom fish. Hope this helps.