I have a Lowrance x135 on the bow and a Humminbird 587HD ci on the Console.I guess the question to ask yourself is What do i NEED in a sonar. Then ask How much do i WANT to spend on it. If you are an amateur sport fisher like myself, basic is always better. If you are more of a hardcore angler,or NEED to have all the bells and whistles, then go all out on the best you can buy. All the major manufacturers use the same technology in thier units, and all have good and bad stories and reviews.
Ease of operation, screen readability,user friendly menus, and after sales service should rank high in your decission making process.
Everyone on here has a favorite, but you are the one using it. I have one of each manufacturer only because my brother took the 2 Lowrance out of his brand new Ranger Bass Boat, replaced them with Humminbird units, and gave them to me. His experience with Lowrance over the years has affected his decission to go with nothing but Humminbird. Others on this forum will have other opinions.
Paul