This story arc was just awesome! I enjoyed the whole mystery revolving around who might be a Skrull or not. Sometimes it was shocking to me that a particular hero was a Skrull, because I wasn't expecting it. They played the part so well. Many of the sleeper agent Skrulls thought they were the actual hero til their last dying breath. Their last words claiming to be the hero they infiltrated. I particularly felt bad for for one skrull, named Z'Reg. He was charmed by the earth and all of the things it had to offer. The heroes that he was bred to hate were now his inspiration. No longer did he want to be a civilian human agent, he wanted to be a super hero. He called himself Crusader and fought alongside his idols. Ultimately he was found out to be a Skrull and shot in the head. The Freedom ring he possessed made him vanish, so it is unknown if he died or not. All Z'Reg wanted was to be a hero. He wasn't like the other Skrulls and fought his own people to save the earth.
Secret Invasion is somewhat lengthy if you include the tie in issues. Around 90 to 100 issues to read! I suggest clicking here if you want a detailed reading guide and summary. It is that extensive!
I absolutely hated how the ending of Secret Invasion concluded. I didn't expect a villain to take all the credit for taking down the Skrulls. He made sure that everyone on national TV saw how he was taking care of the situation. He orchestrated it that way as part of his plan. S.H.I.E.L.D and the Avengers are now in the hands of this villain. The Skrull invasion has ended, but a new Dark Reign begins!