Picked up a 3/8 SAE today. Then I put them next to the Hansen trays.
First things I notice is that the basic dimensions are the same. The posts though on the Kobalt trays are smaller, and the already mentioned square drive holders instead of the 6pt/12pt holders. The smaller posts could be a good thing, or a bad thing. Good in that they seem to flex a little more, and they will hold my old Snap-on's with a small through hole... Bad in that I could see them breaking a little easier... Although the bigger posts on the Hansen rail might be more likely to shear... Hard to say...
The tray itself is the same basic dimension, and thickness. If I put a hand on either end of the tray and torque it, they both seem to have about the same amount of flex.
The marking location is fine with me. With my height (6 foot) in a regular height bottom chest socket drawer I can read either fine. If it was in the top of a top chest I could see it being a little bit of a hassle, but the Hansen ain't much better.

All comes down to personal needs. I need larger fonts, and a excuse to get new stuff...
My Dad's 1/4 Hansen tray on top, and the new Kobalt tray on the bottom.
Bottom.
Top.
My Dad's 3/8 Hansen tray on top, and the new Kobalt tray on the bottom.