Depth Raider is a fine unit and much less expensive than the fish hawk, but you have to use the coated cable. The fish hawk requires that you add an additional transducer.
Coated cable units give more instantaneous readings to your display, provided your cable is in good shape, but they also have more blowback because of the extra diameter the coating adds.
I used to have a moor subtroll, now I have a cannon speed n temp. Both are coated cable units and both have worked well for me as long as I keep my cable in good condition. We use the depth raider on the tournament boat I fish on, and it works great too. Sometimes we have to use a wet rag on the antenna, but the fish hawk failed, and the quicker updates the depth raider gives are nice.