Always keep real voices
Here is the way it works. If you want people to like your flash, then you have to have well made sound. That INCLUDES voice acting. let me put it this way: If you went to a movie and all the voices where, computer-dictated, you would be like "That was STUPID, I just paid 8 bucks to see THIS!". You would hate that movie! The only time C-D voice should be used is on, oh Stephen Hawking? Or a one person in your flash that has it and uses it for a laugh, maybe a robot.
so never use that crap if it is not needed. It really takes away from your flash. even still good flash! 7 out of 10 God LIfe