The reason people buy stands like this is because the only way you can get proper alignment on the normal monitor stand is with the panels vertical to the desk or with them aligned as a flat plane. Any tilt at all on a non flat plane and you end up with gaps at the top or bottom, there simply isn't any way around it.
Three monitors locked on a triple arm, however, can be tilted and raised/lowered as a unit while reducing the desk footprint.
A couple things you have to keep in mind with these - They really are not designed for huge displays like 30". I have three 27's on an ergotron arm and previously had a 20/30/20 setup. The 20/30/20 setup BARELY fit - I was within a few mm of the end of the arm on each side. Three 30's in landscape is an absolute no go. You could probably do it in portrait, my three 27's fit with plenty of room to spare in portrait (6+ inches on both sides). I did my research very carefully when I originally bought my stand and it still barely fit.
Second, the weight becomes a problem. You can adjust the tension on my stand but even maxed out it's barely suitable.
Viper GTS