I've had this tray for couple of months and it is working as it should, though not without inconveniences.
I had to get used to the fact that the tray blockades are in the rails, thus it's hard to return it to the original position after it was pulled out. There should be a grip or hole for fingers under the tray to pull it out, especially due to my keyboard's weight - without it, pulling out the tray is not very easy, though the movement of the tray is very smooth.
However, my biggest issue with this tray is that it's too small for Komplete Kontrol S88. The front keyboard stands are in the air because there's no room for cables in the back (the plugs are taking a lot of space and holes in the tray are too far). To push back the keyboard and minimize the free space, I had to drill an additional hole in the back of the tray. I would consider a special option for KK users or a bigger tray.
I like the fact that there is height adjustment, though it is not nice if there is no one to help. I would suggest Studiodesk to add additional hole near the other two holes in the desk to mount the tray, so the tray could be placed more in the back.
Overall, it's a proper keyboard, but has some flaws that you should be aware of.