John,
That is the Large ICU and the PE foam (the stiffer one). I have the Loka, which is the smaller pack. An XL extends up beyond the opening in the pack so I use the Large. However, this has caused me to think about an XL. There are a couple of things I don't like about the layout, mainly because there are thin places that deform a bit when it is in the pack.
What I like:
-It holds the camera and lenses more securely than fabric dividers.
-Small things like batteries can be stored without the risk of flying around in there. Before I used a Think Tank 4-battery holder, but that takes up more space and is hard to access because of how I lay out everything using the fabric dividers.
What I don't like:
-It holds things very well, but I wonder if too well. As you can see the camera sticks up a bit; the wood grip is completely out of the foam. With the fabric dividers it would move around and deform the ICU when on my back. This one won't do that, so the camera really needs to be where it is because that lines up with the small of my back. If it was up higher near my shoulders that would be uncomfortable and might not be good for the camera either. Choosing the softer Ester foam might be the answer, but I'm not sure any of this is going to be a problem. Time will tell.
-I should have made the battery holes deeper; they stick up too much. These were 2.25", should have been 2.5". I was worried about pulling them out with my fingers because I have no room for the optional finger access holes. But it is pretty easy to pull things out that are flush so I would have them just barely stick up above the surface.
-As I mentioned above there are some things that are too close together. If I did it again I would get rid of the glasses holder and just put them in the top of the pack or keep them on me. I might consider getting an XL so I could spread things out just a little more. I wouldn't use the whole 18" of the XL, but could use about 16". That gets me 2" more to space things out.
In general, if this was for a hard pelican / storm case I would love everything. The backpack is a bit more dynamic, so I don't know if it is really better than std fabric dividers. The camera/back sure is held in nice though. Again, time will tell.
I might try an XL in the Ester foam. But this can get expensive fast...
Dave