The Good: Superman Can Photosynthesize
We're told Earth's environment is more "nourishing" than Krypton's, and that a younger star will especially benefit the young Kal-El as he grows into a healthy alien gentleman. This actually makes some kind of sense! Krypton orbits a red star, likely a dwarf (a red giant would have exploded before any civilization had a chance to take hold). Even the largest red dwarfs have only 10% of the Sun's luminosity, so Superman would definitely max out his health bar here on Earth. Not to mention, almost every lifeform on the planet is solar-powered anyway (notable exceptions: those deep sea nightmare creatures), so it's not a stretch to imagine an alien who could directly convert sunlight into energy like a plant. In fact, we should take a lesson from the Man of Steel! Why are we scrambling around with fossil fuels when he have a wondrous star out there that barfs up enough energy in one second to sustain our civilization for 500,000 years? Check out this cool space-web if you're interested in the future of global solar power.