I've bought a smaller one from TabletMod and had it working after one unfortunate event with an electronic board. It's working very nicely now, I get almost 100% accuracy in the middle portion, with some jitter at the top of the monitor and maybe a few dead areas near the sides.
The build I had was made with acrylics, while durable, seems to be easily broken, especially the smaller parts. Nothing some glue can't fixed though, but definitely would have like it to be mode durable.
If you ask me I think it's definitely worth it.
Here's a picture of my build, made with Tabletmod's part. Zbrushing with it was a blast! Now I am waiting for my cheaper alternative to the Ergotron arm and its done!