I must confess that I have not read many Superman stories. I'm just not really a fan of Superman comics. So I will say right now that if somebody thinks Grant Morrison's Superman isn't true to the Superman character, I can't really argue. I wouldn't know. I've read a few here and there and every time he pops up as a main character in a crossover I've read him, but never consistently. So I'm judging this series completely on its own. How is it on its own? Pretty cool.
This is another comic in which I haven't reviewed the previous issues so I'll just do a quick recap.
First Issue: Cool, but quick, introduction to teenage supes with some exciting action scenes.
Second Issue: Awesome. Superman being tortured and making his daring escape was thrilling, and all the knowledge we learn about his origin was interesting and presented well.
Third Issue: Felt a little rushed. I couldn't believe that Clark would quit so quickly after a couple of people telling him that they don't like him.
Ok, now the fourth issue. This issue is essentially the introduction to Brainiac and Metallo. It features Superman battling the terminauts and Metallo. Like I already said, I'm not really a Superman fan, so I don't have much prior knowledge of these villains, but I like them in this series. Brainiac is really creepy, menacing, and ominous. He doesn't actually appear in full aside from one panel towards the end, but his presence is felt nonetheless. Metallo is mostly controlled by Brainiac, but he's constantly referencing his human side. One stand out scene for him was when he confronted and nearly killed Lois, who he was in love with before becoming Metallo. This issue is mainly an action issue, and it works really well as an action issue. There is a lot of action and Rags Morales does a great job with illustrating it. There are occasional inconsistencies with characters here and there, but the book looks very good overall. Superman's battle with Metallo was really exciting as well, and I actually enjoyed the last minute save from Doctor Irons AKA Steel. I also really like the ending, the military who tortured him only two issues prior now working together with him to take down Brainiac. It’s a cool concept, and it’s actually a little disappointing that this story won't be continued until issue seven (the next two issues are an interlude that I think will be exploring more of Clark's origin and how he came to Earth). The backup is nice as well. I like the motivation and inspiration of Steel, and his fight with Metallo is good in that he has to use his brains to take down the physically superior Metallo.

Overall, there isn't anything groundbreaking or mind blowing here, but the action moves at a brisk pace and there is still enough story and dialogue present so that the issue doesn't feel too fast or lacks story progression.
An exciting issue and I am looking forward to more.
8/10