I'm looking to purchase a fish finder for my float tube...It will also be used on a boat. I'm not looking for anything really fancy or expensive, just something that works well. Here are some that I've been looking at...Please let me know your opinions.....

Eagle 245ds - $100

Lowrance x50ds - $119 (looks just like the 245ds, not sure if there is any difference since they are made by the same company)

Humminbird piranha max 220 - $100
piranha max 240 - $140
565 - $200


all of these are dual beam or greater.. Does that really matter??? Would I be ok with single beam or does the dual beam give me that much wider sonar coverage?

Thanks