I recently bought a Garmin Stiker 4dv and installed it on my float tube. There's not a lot out there on this unit yet so I'd like to tell you my findings so far.
Pros:
Compact but good screen size for I'd say up to 3-4ft away.
Very vivid, bright colors
Quick disconnect dual swivel mount
Great features for the money
This thing has GPS mapping, traditional, split screens, down view imaging and even a flasher for jigging (which I love). Also has a voltage meter for whatever your powering it with.
Lots of customizing you can do also. There's water column zooms, number lay overs...there's more but I'm not a tech kind of guy and I've only had it out twice for a few hours.

Here's the con's and the transducer question

The cons: I really only have one con, the power cord and transducer cord are the female end of a tiny 4 prong plug set up. The plugs have notches so they line up one way but the prongs are very small, mine was either damaged during production or was off just enough to bend over one of the prong tubes on the power cord when I hooked it up. Mine was replaced the next day where I bought it from but that could ruin your day. The new cable went in with no issues and is a very solid, tight connection. My suggestion is to leave it connected and disconnect the cables at the battery or get a quick disconnect for the battery like I did.

Now to the question...I have the transducer mounted to the outer left side tube and points to the left (if I was sitting in the tube looking straight that would be 12 o' clock, the transducer points directly to 9 o' clock). Everything seems to work fine but one thing is when I use the flasher, my jig seems to disappear once in a while. Should I mount it pointing at the 12 o' clock position.

So far so good on the Garmin. I was out for over 3 hours yesterday and only used .3 volts and that was with using the DV imaging and going back and forth in all the screens on daylight brightness.
I can do a separate post if anyone is interested how I mounted it to the tube.