Stan,
Which monitor arm is best for will depend on how you plan to mount it and what kind of range you are looking to obtain vertically and horizontally and weight of the monitor.
For a typical desk, I would recommend you use a grommet mount instead of the typical edge mount especially if you are planning to use a 30" display. The Humanscale arm you are looking at is only good to 20lbs so it may not be able to handle your 30" display.
If you are planning to use it in a sit to stand set up, we found the Humanscale arm did not have enough range if you are over 5'4". We have had good feedback with the IOP arms in sit to stand settings at our facilities.
If you have an oddball mount issues the guys at ICW USA have always been very helpful with my inquiries.
Mike Pierzchalski, Ergonomic Consultant
Vancouver Island Health Authority
