Great issue!
At last this is getting interesting, in general I think that all the brightest day arc has been a little slow but this issue was great.
The Good
First of all, the art has been very good very rich and definitely add a lot to the issue. Martian Manhunter at last is starting to take a more important role in story which for me is great because I have always like this character and what a shock to see miss martian like that at the end definitely a great cliffhanger. It's interesting to see the revelation about Mera's past, I think it adds a new layer to an already great character and now we know who was the girl who attacked Mera and Arthur last issues was. I must say I have never been a fan of firestorm but his part was very enjoyable, maybe I''l reread his previous parts in Brightest day. The part with Boston brand and company was good as usual, but it was a little slow compared to previous.
The Bad
No hawks and still no word on the white lantern, but it wasn't really bad since what was in the made up for it. Still nothing new on Jackson, but I guess we'll be hearing from him very soon. My only complain is that I still feel that all the brightest day story are a bit disconnected, Dove and Hawk are the only ones who have important roles in more that one volume, the stories should be more connected to each other.
Finally
I think this issue was very solid, a lot of cool things happened some of which answered a few things and others have created new questions. If you can give it a read it's worth it. Now I'm gonna reread Brightest Day 1-5 in case I've missed something.