You can use many words to describe Bowie, but "easy" will never be one of them. And, ye gods, I can't even imagine trying to reproduce anything resembling "Life on Mars" on a guitar. Possibly this is because my guitar skills are significantly worse than my piano skills (I can just about manage the easier folkier bits of Simon and Garfunkel), but mostly I think "Life on Mars" is one of those quintessential piano pieces. See "four pianos and a death wish", above. Guitar is for things like "Quicksand" or "Queen Bitch", to which a piano does no justice at all.

Then again, it's the same magnificent hubris that leads me to try and reproduce Arcade Fire with insufficient skill on a single piano. I salute you, sir.