A pair of Blackburn 2'Fers are excellent to-be-seen lights. They can be set to white or red, steady or flashing. Very versatile, compact and lightweight. I like 'em as helmet lights. Excellent peripherally visible lights too, a huge advantage in a to-be-seen light.

But they aren't particularly useful to actually see where you're going. I had to use my Blackburn 2'Fer once as a headlight. It was just barely adequate for picking my way home carefully for 10 miles at about 8 mph on dimly lit and unlighted roads.