Does nuclear fusion release more energy than nuclear fission?
Yes, Fusion generates more energy per unit mass of fuel.
Fusion reactions release 3-4 times more energy than fission reactions. Getting to a sustainable fusion state is a bit more difficult, and requires a lot of energy itself. That is why the (relatively) less energetic fission is used for current power production.
Initiating and controlling fission is relatively simple because it only requires regulating a spontaneous process instead of initiating a process with a very high activation energy requirement.
A good comparison and discussion of the two can be found here: http://www.diffen.com/difference/Nuclear_Fission_vs_Nuclear_Fusion