WARNING: Arr! There be spoilers ahead, matey!
I know a lot of people are waiting until Grant Morrison's epic Seven Soldiers is completed before passing comment, but I just got the opportunity to read the first four mini-series in one go, so I thought I'd venture a few thoughts.
First off one has to acknowledge that it's an ambitiously mad epic experience. Kudos to Grant for even attempting it. I can't think of anyone this side of Alan Moore who would even try to do something like this. It also makes me think of Kirby's Fourth World. That's the only other time I can think of where a single writer produced several monthly comics with distinctive individual flavours to tell stories that were part of a larger experience.
Which is not to say individual titles or stories are not without faults. There are times in almost all the titles where the Metaphysical bullshit detector veers dangerously into the red, but what really struck me was that most of the titles feel a bit cramped. In Manhattan Guardian the first three issues are about the Guardian's relationship with his girlfriend and family, then they are suddenly dropped and we're in major flashback city with very little set up. In Klarion our hero spends several issues escaping to the world above and then you blink and he's already established as part of a gang. I haven't read up on the background to the production but I have this sneaking suspicion that maybe the original plan was to do seven miniseries of seven issues each, and as part of some compromise with editorial it was reduced to four.
Things I liked: Each of the different series was actually different. While strands of meta-plot wandered from one to the other the stories themselves were quite individual.
Things I didn't like so much: The apparent compression of storylines, the metaphysical BS, and what the hell was the point of revealing that the Shining Knight was female five pages before the end of the story? The only relevance it seems to have is to add some intensity to the confrontation with Lancelot because we are informed that she's always had a thing for him. Surely that would have been even more poignant if Justin had been male? Knowing that she is female doesn't make you think "oh, that bit from earlier in the story suddenly makes a lot more sense" so it has all the surprise value of pulling a sock out of a hat - you weren't expecting it but you don't really care. I can only hope that it becomes relevant later on.