This is a great keyboard tray for a standing desk. It gets out of the way and has enough room for my full-size keyboard and trackball mouse. The height adjustment is easy enough to use, but looking back on things, I would've probably gone for the simpler height adjustable under desk mounted keyboard tray. The swinging out adjustment doesn't do much for me.
"This sounds like a four star review?" Well, it might've been, if not for the arduous installation process. The instructions tell you to hold the keyboard tray up under the desk to mark the locations for pilot holes. This is, unfortunately, near impossible. The arms of this keyboard tray are not fixed into place - they can slide into the next "locked" position if you push the tray too hard into the underside of the desk. This isn't exactly a light tray, so holding it still without changing the arm position while accurately marking the pilot holes is insanely challenging. So much so that I couldn't manage to do it. I ended up cobbling together a makeshift stencil out of a taped together piece of cardboard and went about it that way.
If Vivo wants to commit to including a stencil for mounting these trays, I'd gladly change my rating to 4 stars. Until then, I have a sour taste in my mouth when using this keyboard tray, and again, the simpler option would've fit my needs and might've been easier to install since it doesn't have these swinging, adjustable arms.