I find stiff is good for power , makes getting on waves a bit easier....BUT I find stiff paddles gives me me aches and pains and tire me out a lot quicker than my flexible friend..
I went from super stiff homemader to a nice flexi super light kialoa shak'pu,,,, the difference was amazing.
The kialoa range, keep getting a great rap on this forum, every other paddle i've compared it to,feels stiffer and lifeless. Worth a look

For me at the mo; flexi is the go.