I did not find a web site that offers comparison images of all the current
types of electronic charts. This page is dated but gives you a feel for
the differences in the visual presentation of raster and the various
proprietary vector charts brands:

Great link. It looks like there's a lot of details there in those
vectors.... I've found some S57 med maps and I had a go just to "try before
you buy" and the detail is zero!!! Storing vector data is nothing difficult
nowadays, and computational power is fair enough to recalculate and redraw a
chart. The maps you've pointed out show exactly that it is possible to store
enough data into vector based products like if they were rasters.

I'll try to download some of thos NOAA S57 maps to get an idea.

Thanks for your precious thoughts