I have had a Kalais for a few months. These are my observations:

* The lower back pad is not centered on my pack. It's not a problem because the hip belt can be centered, and the padding isn't thick enough for my back to notice at all, but it does make it look less professional.
* I don't like the roll-top closure that buckles down the sides. I would have asked for a drawstring if I'd realized it had that style. I had to switch out one of the side buckles with a top buckle so that I could close it like a dry bag, because it had both female buckles on the top and both males on the side. The female buckles only have one slot for the strap, so after switching them out I can't tighten that side strap. I don't plan to use the side buckles anyway, but it would be better if the pack could be closed either way.
* The hip belt has very little structure, which is fine for me at the loads I plan to carry. I don't think I've had more than 17 pounds in the pack.
* The back pocket doesn't have too much room when the pack is full since it doesn't stretch.
* The side pockets are large but the elastic top keeps things in pretty well. I usually carry a 1L Platypus in each one and that leaves a lot of extra room. Too much room sometimes since they can slide away from my back if there's nothing else in there.
* I haven't tried it without the stay yet. The "V-stay" is not really a "V", more of a squared-off "U" and it doesn't go out to the edges of the pack.

Let me know if there is anything specific you would like to know.