Despite having themed army, I'm painting Questing Knights in various colours. That's because of fluff - they aren't vassals of baron, but knights who joined the battle during their quest for the Grail.
Yellow on white is never a good idea.... the paint job could use more deoth thru highlighting and the bases seem hurried. The banner is intricate and a pain to have done up I'm sure, a pretty decent overall job ;)
This is a really nice, impressive unit. I like the clear heraldry you have painted.
The only nitpick I have is that you have broken some of the basic rules for color combinations in coats of arms (i.e. metals white and yellow must always be next to colors, not to other metals), and that leads to some patterns which are hard to discern from a distance (for example, yellow on white or red next to green).