First I should note that watts is a measure of power consumed. It is not a measure of light or efficiency.
Generally the more efficient lamps are shorter lived. Lamp choice is a trade off.
In general most people will not notice a difference in light until that difference approaches 100% So if you increase the light output 50%, you likely will have a difficult time noticing the difference.
I believe that in most situations, improved beam design and clean clear lenses offer the best chance for improved visibility.
I have found good E-codes offer the best choice for me. Your mileage may vary.