Punishment Or Reward

Rashi says that Yisro came because he heard about krias yam suf and the war with amalek.  A few pesukkim later, Moshe repeats the story to Yisro and the following possuk (9) says Yisro was happy about all the good done to Yisroel which Rashi says refers to the man,  be'ar and torah.  Why is Yisro especially happy over these events more than the original information?  And according to the interpretation of Rashi that he was upset about the destruction of Egypt, why did he only feel that now?  Why does possuk 9 use the name of Hashem referring to the middas rachamim as opposed to the first possuk of the parsha which uses the name of din, Elokim?
At first Yisro heard about he great demolishing of the Egyptian kingdom, the defense against the Amalakies,  and understood that they deserved to be punished for their crimes.  However, that perked his interest, but didn't yet demonstrate there was any special quality to Yisroel.  It was an act of din against tyrants.  However, when Moshe told him that that's not the whole story, God has taken special care of us, he has done miracles for our sake alone, there has been chesed extended to us, that proved there was something special about Yisroel.  That's when Yisro felt happy for the special relationship with Yisroel.  He simultaneously now felt bad for the Egyptians because he realized they weren't punished just for their actions, but to demonstrate a lesson to Yisroel as well.  They were selected to be the puppet's of God's might (Meor ShebTorah citing Rav Mordechai Man.)