It is not important at all! Contrary to what most consumers are led to believe, solar panel efficiency does not affects the power output from the solar panel. A more 'efficient' panel does not produce less power than a less efficient panel. We normally see efficiencies of 12-14% for crystalline solar panels and less than 10% for amorphous solar panels. However, this efficiency refers to how efficient sunlight is converted to electricity, this only affects the size or surface area of the solar panel.

Power output, on the other hand, tells you how much actual power is produced. For example, a 80W rated polycrystalline solar panel will give you the same power as a 80W rated monocrystalline solar panel. It is as simple as that. To a lightbulb, it does not matter whether the solar panel is 10% or 100% efficient. The lightbulb will work as long as 80 watts output is supplied to it, no matter what effeciency of the solar panel is producing it.