Efficient and modular
A bit expensive but seems to be very solid and durable.
When used as a laptop stand (i.e. a horizontal tray instead of a vertical one for a monitor), it does the job perfectly. To date, the only thing missing from the LDLC catalogue is the VESA laptop tray to complete this article.
The mounting system means that you can - if you wish - only use the end arm without the extension to reduce the length. This is what I did.