God i post too much.....anyways what would you rather have?

Garmin 160 blue http://www.garmin.com/products/ff160Blue/

Eagle seafinder 320df http://www.eaglegps.com/Products/Sonar/fishmark320.htm

buying 160 blue today

Get the Furuno LS4100 : http://www.consumersmarine.com/products2/picklinkcat.cfm?cat=31&menu=sounders

works pretty good, fairly cheap on the internet. only complaint is the limited memory

I'd go with John. I put the furuno LS6100 on my proline this
season, and I am marking more fish than i ever did.

It is awesome.

It looks like the 4100 is basically the same unit.