I think a lot of the comparisons in that link are stretching it a bit, but with images like the first one below, I have a hard time believing this guy hasn't been basing at least some of his art on Bleach. There's no way some of these could be coincidental. Of the ones you've posted as examples, I think the 1st one is pretty damning, but the 2nd one seems like a fairly common attack pose. I'm willing to give him the benefit of the doubt on that one--it may just be an action cliche, rather than an outright theft.

I also thought that there were some comparisons that were unlikely to be coincidental due to thematic similarities, and even the shapes of the boxes on the page. The one where the top panel of the bleach comic had a Hollow sort of leering downward toward the panel with the terrified girl below it, and the Incarnate example had a similar skull-demon-thing looking down toward the lower panel with a very similar terrified girl is a good example of this. In addition to having very similar monsters overlooking very similar girls, in what appear to be very similar circumstances, even the shapes of the panels are similar. The face-palm pics look too similar for coincidence, too.

A lot of the comparisons between the girls don't carry as much weight with me, mostly because I think a large number of manga girls are pretty much interchangeable anyway. I suspect you could find comparable poses and facial expressions being made by doe-eyed generic 14-year-olds in just about any comic. Even so, it's suspicious how well some of the faces lined up when superimposed, particularly around the nose area.

I don't have that much of a problem with artists basing forms off of other artists works, so long as it's not frequent and they have either made it a subtle part of an otherwise original work, or are making a clear homage to the source artist. When you see all of these comparisons in one place, it makes Simmons look really shady, but I'm not sure I would have been as likely to see some of these pictures as plagiarism if I hadn't come across them in the context of a page full of other purported plagiarisms.

When I first started writing this answer, I was going to say that, over the course of a series, what I've seen doesn't look as heinous as the fanboys are making it out to be. Then I read that this was a 3 issue mini-series, and I'm back to thinking he's moved way past "homage" and into "rip-off" territory. It does look like he may have traced parts of some of the Bleach pictures, which is an absolute no-no in my book. I didn't even think tracing was acceptable when I was 6, I can't see putting up with it from a supposed professional.

I'll be curious to hear what Simmons's explanation for these "similarities" ends up being. I would hope he has the good graces to admit he's been cribbing some of his designs from Kubo (and maybe others). To my eye, it looks like maybe he needs to take some time off from drawing professionally to learn how to draw forms without relying on other people's work for models.