Yes, I get on with it very well and recently discovered how to set the unit to 'head up' rather than 'north up' which made it even better. I feed position out to the VHF and AIS in from the VHF. Need to keep the user guide handy for the first year or so but you do get used to the setup and menus. I have mine set up with a second power and data lead at the helm so I can choose between having it inside or out. I prefer to plan on the laptop but havn't yet worked out how to pass waypoints across but almost certainly possible if you read the book and set up the connections correctly. Excellent value for money in my mind.
I bought a Garmin 451 at Christmas and installed it earlier in the year. Excellent value compared to the competition.
Slightly smaller than the 551 but otherwise very similar I think.
Haven't had a chartplotter before but have found the menus and general configuration quite simple and intuitive, so quite pleased so far.
Have only used it for a shakedown holiday run at Easter so far which was on inland and tidal rivers, but planning to use the plotting & charts in July.
We have ours hooked up to a NASA AIS, does the same thing but cheaper.
Haven't experienced its benefits in anger yet.
One thing that did impress me the other day, I updated the built-in charts using a 4Gb SDHC card.
Once saved, the updated version is saved internally in the chartplotter - no card to lose, have stolen or fall out.
I have had a Garmin 556 plotter at the chart table for a season and it is an excellent piece of kit - not sure of the difference in spec with 551 though (screen size/resolution?). The display on the Garmin, especially of AIS targets, is far better than on the Standard Horizon plotter (CP180) that I have at the helm - also the menu system is easier to use. Unfortunately the nav pod at the helm is too slim to take a Garmin or I would have one there too.
Used the Garmin 5I5s for the first time a few weeks ago and found it invaluable, in fact I would have been stuffed without it e.g. In thick fog where I just couldn't see anything, even the shoreline let alone the next channel marker along East Head to meet up with two other boats before Chichester Entrance - I relied on it totally to guide me along the channel and the fog lasted all the way to Gilkicker Point although it wasn't quite so bad along the coast as the picture shows.
People said you don't need a GPS in the Solent, and I replied but what about foggy conditions!! First time out with GPS and it proved it's worth