1. It's more flexible, much easier to handle and doesn't require poking holes into a boat. I sometimes travel to different states, I don't take my boat with me, but rent a boat a the destination. And in a case like this, the portable fish finder is just great to have. 

 

2. The unit that I have features Down Imaging which is quite nice to have, for a better understanding of the location of the fish in relation to various rocks, trees, logs underwater. However, due to this feature it was a little bit more expensive. I wanted this feature especially for carp and catfish, but to track fish it's not really necessary. So, if you want to save a few buck there are plenty of other portable Hummingbird fish finders that you can choose from, for example the PiranhaMax models.

 

3. It has a DualBeam Plus sonar which means you can observe in split-screen both the 75° and 45° returns. However, I have to add here that even though this unit it's said to be reliable in waters up to 500 ft. deep and the Down Imaging for 250 ft., I wouldn't recommend it for sea fishing. However, for lakes and rivers, up to 150 ft deep, it's a great tool to have. 

 

4. Another aspect that I like about the 570 DI Portable fish finder from Humminbird is that it came with its own case. So, it's easy to pack. Also, it has its own AGM rechargeable batter, which lasts me for about two fishing trips. 

 

5. The final word that I want to put in here in favor for the Humminbird 570 DI portable is its price. I got mine for $361 which I think it's quite a fair price for a tool that helps me find at least a nice catch every time I go out on the water.