Sacha - Whenever you think it will work, Ezio has situations that he creates that are slightly negative and a well placed 4B can avoid instant retaliation, it also has a TC on the way back so highs won't catch you. I like to 4B after 2K on hit, 2A or 2A+B on block, its a player v player thing.
Seran - Very easy to learn, hard as hell to be consistent with.
Harry - Because Namco is obviously the worst company ever