Power, features, functions and price are ways to compare different fish finders. Choosing the right fish finder depends highly on its intended use and the type of water being fished. Accurate comparison of different fish finder models can ensure that the fisherman doesn't buy more or less than he needs.
The amount of power behind the sonar beam dictates the level of detail and depth of water that can be accurately scanned. More powerful units typically cost more so shallow water anglers do not need the same power as deep sea fishermen. Features and functions such as side-scanning sonar or a down scan model, GPS functions and networking capability are valuable elements to some, but for other fishermen price may be a deciding factor.