In terms of FFs, like many things, you get what you pay for.
I don't think an expensive fish finder makes you a better fisherman....time on the water (and lots of it), in your regular fishing grounds, does.
However, having some level of depth and what is below you (structure, flats, highs/lows, weeds, etc) does help quite a bit when finding and catching fish....that's what the pros look for and they are under time constraints.
For me, the below average fisherman, I stick to basics that are high quality. I use a Lowrance HDS Live 9. When it goes on sale, I will pick up a second unit and install it at bow (for bass fishing). I currently use my console unit when trolling and all other fishing. The bow unit would simply be for convenience.
The Eagle is a new unit and budget minded, so time will determine its worth. For now, HDS is the unit of known and proven quality, not to mention its 3 in 1 Active Imaging Transducer is one of the best in terms of what I mentioned above.
It comes down to budget, how often it will be used, how serious you are about fishing, and what YOU are willing to spend!