Pluses:

water-proof,
light-weight,
tough,
pretty crease-proof,
stores in a small bag for easy storage,
opens up to a large size--large enough to cover my back-pack when biking,
snaps shut under the arms to reduce flapping,
is bright yellow for good visibility.

Minuses (only for biking):

Still flaps which can be a bit dangerous when biking as it might catch on something.
Does not cover arms or legs- so need to wear something under it if the weather is cold and rainy. I use a regular rain jacket and pants for that purpose.