I am considering purchasing a Raymarine E80. Will be using the device primarily for sonar, chartplotter and gps. The other functions are great as well, although I prob. won't use radar at this time $$. Does anyone have a suggestion of a good unit? This is for a dive boat. What about a C80, or another brand alltogether? The E80 appears to be user friendly and I like the screen software. I like having the ability to plug my laptop computer in to retieve data. Cost is always a factor, although with e-bay, I can always find good prices. Help!!