PHNX - I paid $150 from boaters world for the f2100. I can't remember what I paid for the f41. These units are simple to install . . . just follow the directions. Flowscan is the only unit I know of with a digital and dial readout. My brother had a flowscan for 3 years and the gauge rusted up real badly.
Jim from Boe Marine put in a good word for the Lowrance units. If I get another one . . . I'll probably go with that one.
http://www.lowrance.com/Marine/Products/LMF-200.asp