You will be better to find them by yourself, not all the question should be write on this forum you have to find in other site. So when you already know and you have analyzed it you can ask here and make a disscussion. And I'm sure you make this thread only for to add your history post and you won't be commenting on this thread anymore. It will be different if you have known about the proof of stake system and have knowledge against it so you will be disscussing and answer to another user's post so as will make this thread to be useful for someone who didn't know the proof of stake.