Pros: great graphics (pixels). Awesome detail and outstanding price.
I am so very happy with my Raytheon GPS 420. It has an extremely easy to see/read 6" screen. Its back-light screen is kind on the eyes at night (4 or 5 different back-light levels) and is super easy to read during the day.
Compact enough to put just about anywhere and looks GREAT flush mounted. I added the Navionics chip (West Marine $199.00) for the S.FL and Bimini area. The detail added by this chip is awesome. Showing depths, partial Light List info, ATON information and even port information such as what accommodation are available in any given port.
My only problem so far has probably more to do with something I've done more so than the machine. I've linked the GPS to my Standard "DCS" VHF radio and now the radio has a bit more static when the GPS is turned on. When I turn the GPS off, the static goes away. Most likely it's a grounding problem that I need to fix - but it hasn't caused any problems yet.. Like I said - I'm sure it's something I've done!
So far it has been an outstanding investment and for only $399.00 at Boaters World - I should have bought one awhile ago.