In Response to Threads about Overall Usefulness
I've recently invested in a Garmin plotter with Bluechart (CD vesion for a PC, with a download lead and memory card). Previously I'd used a Garmin handheld, which will now become my back-up.
Whilst I support the view that a plotter gives you more options out at sea, better situational awareness etc, the real transformation for me has been at the route planning stage.
What used to take me whole evenings at a time, laboriously marking up paper charts, extracting lat and longs for multiple waypoints, then painfully entering into the hand-held, can now be done in literally minutes with a few mouse clicks, a simple download, and finally a print-off (for 'first-resort' back-up purposes) of the relevant bits. Basically it's put the fun back into it. I can now do most of my pre-planning at work during lunchtimes when it's convenient for me, and I suspect on future dive trips the time saved will occasionally save me from having to turn down the pub trip.
Doing it this way you also get the great 'toy' element of being able to reverse download (back to your PC) the actual tracks followed, and can view these overlaid on the on-screen chart. Great fun! (Might even use these to refine my waypoints).
And the accuracy of the charts I've used appears to have been bang-on so far.
Twenty years in the aircraft industry, five years boating, and I still can't spell propellor ...