Agree with Brian, even on a big plotter in anything other than a calm sea it takes you all the time to press the right button, never mind trying to pull up some data on a buoy, or scrolling around on high zoom.
Never used C-Map but like blue chart and the ability to plan a passage on the PC then download, all included in the price (if you get the CD version) Think this is extra on C-MAP.
Only down side is when you need to update its the full price for a new chart again (I think).
Like Garmin plotters, but dont rate their sounders if that helps, in case your looking for a combined unit.
Think colour is well worth the money, but not sure iof it was between a big mono or a small colour
I suggest go to the boat show, stick to the main ones that will stand up on ribs (waterproof, ask other ribbers not the sales guys as they tell you you can go diving with them all !!) and see which one you like best.
We went ready to buy a Raymarine and came away with a Garmin when we bought at the boat show.
Happy New Year