Madoff was sentenced to more prison time than many murderers. Murder and fraud may not be equivalent, but that does not mean that one must necessarily be less serious than the other.
Financial crimes in the US carry some pretty draconian penalties in terms of sentence length. They have to, because if people think financial institutions are going to run off with their savings the whole industry collapses.
In Madoff's case there was an additional issue - the people he defrauded were mostly wealthy and powerful.
