The M605 Marine Blue is one of my two M600 size blue demonstrators. I think this one is the better looking of the two due its silver (rhodium) furnishings.
I own three Richard Binder ground 0.7mm cursive italics, one is a M250 nib, one is a M800 nib and this one, modified from a M600 medium nib. The 0.7mm line width is the sweet spot for my normal writing size. This nib is a joy to use and makes my writing look good.
Ajisai which is Japanese for hydrangea is lovely blue colour that shades slightly but doesn't appear to sheen.