545s
Bought the 545s (with internal antenna & sounder) and used it on one trip from Miami to West End Bahamas overnight in rough stormy weather. Mounted on the console under a sunbrella bimimi with pools of water, in rain, it soon lost signal. Next day reinstalled and connected old, external antenna, not covered by bimini, and ok since then.I find the interface confusing and have not yet understood how to use it easily. Can never find way back to features I know are there.Subscribing to XM Weather Radio, Seaman's version, gives LOTS of good info including real time weather radar. The 545 is also one of the few allowing subscription to XM Radio for entertainment. Have not yet checked out the sounder function. The 3-D and underwater views are awesome.Due illness, I have minimal, one-trip, experience with this unit and none since June, 2007.