It depends who you are talking to, which side of the revolution, the winners or the losers. Whenever a revolution takes place stemming from people in common cause trying to overthrow a dictatorship or oppressive government, I believe that it is a good thing. However, let us not forget, that the work is not over. A revolution sadly enough, is often the easiest part of the process. Agreeing upon and establishing a government for the people is the greatest obstacle. Getting people to revolt often means that they are at the end of their rope, building a consensus amongst different factions requires time, patience and ways to subsidize an economy that often hasn’t properly worked in years.
A more blatant example of when a revolution has gone bad, is when the end result of the revolution is just a different dictator. The previous dictator successfully overthrown, so, yes the revolution was a success but the installation of a different dictator or tyrant negates any triumph the people may have enjoyed. In this circumstance, probably the only winners are the same wealthy elite who do not care who is power as long as their wealth isn’t compromised.
I forgot which movie, but some crazy character in an action movie said that revolution is a tricky business and that is the truth. The Middle Eastern and African “spring awakenings” will be testament to how risky protest and revolt can be. The world is watching how they Arab nations will proceed from here.