What is CHIRP?
CHIRP is the future of fishfinding. Where a traditional fishfinder works on discreet frequences (usually 200 and 50 kHz), a CHIRP sounder sends each pulse over broad spectrums of frequencies. This makes a big difference, because one frequency sees what another frequency misses. The result is a CHIRP sounder will show detail that would otherwise be missed and separate individual fish that would otherwise be shown as a blob. This may sound like marketing hype but it is not - anyone with an insight in this field can tell you there is no question CHIRP is a huge leap. All the big producers are moving towards it: Garmin, Simrad and Raymarine now has it, and Furuno seems to be working on it. You will not see top shelf sounder modules in the future that are not CHIRP.
If you want the best fishfinder money can buy, what you need is a network plotter with an external CHIRP sounder module. That is the ultimate solution for a larger boat. If you use a smaller boat or are on a budget, the first and only unit with an integrated CHIRP sounder will be available early April, the Garmin GPSMAP 721xs. I am biased because I work for Garmin, but google around a little bit and check out what people are saying about CHIRP.