I think it is a great idea even if it only becomes an entry-level effort to work into a more sophisticated unit. But, I want to get one because of the simplicity of hanging it over the side of my kayak without any mounting issues. So, awhile back, I posted about it in the kayak section, got one response from someone who owned it.
Here is the message in bold print:
depth and surface temp accurate. bottom floor scan so so. difficult to tell if rock hard bottom vs sand vs mud. not so good at structures. grass show up as green but branches do not show up.
as far as fish, it can be difficult to distinguish bunch of bait fish vs a real fish. the icons do not help at all. plus if you are casting the deeper the splash will scare the fishes away in shallow water. unless it is LMB, I've had one try to eat mine.
I did not have any bluetooth connection issue with deeper. I have used the deeper for 4 hrs and still had charge.
I'd rate deeper as 6/10.
I actually think a rating of 6 on a 10 scale sounds great, that it is an accurate device for water temperature, depth, bottom contour, battery life seems more than adequate, no connection issues. The limitations seem to be in some of the structure resolution (branches) and that it isn't as sophisticated as some more expensive models at determining fish versus bait fish. And, this reviewer was not the first to mention to just turn off the fish icon thing and learn to spot them yourself.
Well, if you can use it to determine bottom contour, some structure and bait fish, that ought to put you where you want to be.
Please post back your results!