Thanks Yani for recommending the 728.
I saw your post (2 weeks ago) and started doing the research on that unit and comparable units. I basically found that this unit had the most power/pixels before you start paying a lot and upgrade to color. After my research I found one on e-bay for about 50 bucks cheaper than MSRP (I know no warranty, but I'll deal with Hbird if I need to) which fit my budget of a recently graduated college student.
As far as how any FF works, Lowrance has an excellent tutorial that describes with pictures and video how exactly they work and why we get arches.
http://www.lowrance.com/Support/Tips...onar-Tutorial/
I imagine the difference will be like night and day compared to my 100 (RMS) watt FF I'm currently using. PS: Don't be fooled by "peak-to-peak" measurements, they are a fancy way of making the unit look more powerful than it actually is.