I have a Standard Horizon CP180i. It uses C-Map Max charts available on a memory card (approx £120 for English Channel - larger and smaller areas are available). It came with the boat so I have not compared it to other brands. It has loads of info available (tides, marinas etc) and a clear screen even in direct sunlight, the controls are easy to use, even at speed. Some aspects (like route planning) are not as intuative as they could be. I like the tidal flow arrows and it is the perfect size for a sports boat. I also have a Garmin GPSMAp 76CSx handheld; a great, easy to use unit both on the boat and ashore - gives me faith that Garmin would be the first brand I would look at for a full size plotter. If I was in the market for a new plotter I would go along to Southampton Boat show and try them all.
Better to be ashore wishing you were at sea, than being at sea wishing you were ashore!
Monterey 214 FSC; 'Tenacity'; Devon