I have a deeper. I received it as a gift about a year and half ago. I did get the opportunity to use it quite a bit before I left the country for an extended period of time. I wish I was able to give it to my neighbor for T&E before I took off. Oh well. I use it on a lake about 10-15 acres with a large dam on one side from a small fishing kayak. The unit reads bottom contours and bottom density well. Most of the lake I fish is less than 15 foot deep.
I have not had the unit indicate any structure or any fish, this could be due to the fact the fish were <5 feet or less in depth and there maybe no structure in the main body of the lake. It does indicate vegetation such as hydrilla and grass.
In <5ft or less the unit would be pretty useless, I can see down that far anyways.
I will be taking the unit out to a main highland lake to see how it compares to my low end humminbird unit installed. I know there is ample cover placed in that lake and it will be a great learning experience.
One thing i really do like about this unit is called boat mode. Boat mode tracks and essentially contours the area via your GPS, this works pretty well and I was able to contour my whole 10-15 acre lake in about 5 hours of fishing over a couple of fishing trips. This is pretty useful.
As for battery life it is usually running out by the end of my fishing trip. So 4-5 hours. temperature does have an effect on this unit. It also drains cell battery so I would recommend you either use an old phone or charge yours completely(although mine does last through the day). You can also do what I do nowadays when I could be living without power for a few days and have a small portable recharging unit handy. If you have a tablet I would use that. Tablets can be found on websites such as Amazon for under 50$. You dont need anything fancy just enough to hold a charge and activate bluetooth.