It is horribly inefficient and takes way too long. Even if a judge decides something, people may simply appeal to a higher court. This can go on and on until they run out of either courts or money. I've read about legal cases that began in 2002 and only finished in 2013. It is likely that the defendant will be free during this time. Also, prison sentences are 30 years maximum.
American legal system seems to move much faster. They apparently encourage people to make deals and bargains rather than risk legal defeat.