There is quite a few of solar panel makers on the today. Not all of them are the most efficient, most valuable or less expensive.
SunPower makes the best solar panels in the world and Kaco makes the best inverters in the world and Direct Power and Water makes the best mounting systems in the world. There was a research conducted by ENF among directors of photovoltaic installation companies in 45 different countries.
So as a factory which are making Solar Panels there are:
1.) SunPower (USA)
2.) Schott Solar (Germany)
3.) SolarWorld (Germany)
Best Product Quality: Sanyo (Japan)
Best Value for Money: Suntech (China)
Concerning Solar inverters:
1.) Kaco (Germany)
2.) OutBack (USA)
3.) Mastervolt (USA)
Best Product Quality: OutBack (USA)
Best Value for Money: Kaco (Germany)