I have a Furuno 600L and a friend likes it so much he went to buy one... Superseded... to the 620.. He bought one and I installed it.... I've been on his boat a couple of times with it. It is brilliant!!! I'm thinking of e-baying my 600L and buying a 620!!!
If you need an operators guide, they can be downloaded (but can be hard to find) or you can PM me and I'll email it to you....
I just bought a 620 plus from Boaters World... $ 799. w/ temp./ transom mounted transducer included, and it just came in yesterday. Man it's gonna beat the heck out of my 160 Garmin!