One major difference between the two is HelixPro is a spline shape plugin and Helixometry is a geometry plugin. A major benefit to the Geo version over the shape version is the ability to control the thickness of the object from start to finish. As an example users can taper the thickness of the helixometry version from start to end, similar to what you would see on a tree branch of hair strand. In order to do that in max using the Helix Pro version you would be required to make several spline shapes and a loft operation. Another benefit to the helixometry is the added ability to create non uniform radius.