Solution-processable metal-halide perovskites recently opened a new route towards low-cost manufacture of solar cells, and currently meso-superstructured solar cells and solid thin-film planar hetero-junction show record efficiencies. Based on group theory analyses combined to state of the art DFT calculations, we demonstrate that such hybrid perovskites are natural multi-bandgap and multi-valley materials, leading to a broad absorption across the solar spectrum and attractive charge transport properties. Our results further suggest that polymorphism may lead to exciton screening and reduced carrier mobility. CH3NH3SnI3-xBrx is proposed as an alternative to circumvent polymorphism at room temperature and toxicity, and is likely to offer environmental friendly materials for photovoltaics. We believe that the past research effort invested in the field of conventional semiconductors provides forefront concepts and tools to unravel our understanding of this new class of materials.