Garmin, Lowrance and Humminbird are some of the most commonly reviewed brands. On Amazon.com the Garmin Echo 200 is well-rated at its price point. For models with better depth imaging and both down- and side-scan technology, both Humminbird SwitchFire and LowranceStructure Scan are well-rated devices.
Portable fish finders are generally the most affordable, but are often more basic, with fewer features and without GPS. At the lowest price point, both the Garmin Echo151dv and the Lowrance Elite X3 models are fairly well-rated. In the mid- to high price point range, the Lowrance Elite-4 HDI and Lowrance Elite-5 HDI receive positive user reviews. For models in a higher price point, the Lowrance HDS series are well-rated on Amazon.com, but with fewer user reviews.