The EasyRig was designed to take the weight off of the neck and shoulders for operators who often end up carrying large cameras on their shoulders for longer periods of time (eg. documentary filmmakers, news cameramen, etc).
That's what it does and how it works. Unless you do need it for that purpose you're better off without it, since it'll most of the time only take away from your control of the camera.
As far as differences in movement goes, it's pretty much the same as if you'd just use a standalone shoulder rig, and that's the whole idea of it.
Their is lot of difference between easy rig and regular shoulder mount.
I am having same model of easy rig that is Flycam Flowline. The only difference is price, the price of easy rig is double of Flycam Flowline and quality and features seems same. I using it form last 3 months bought from flycamdslr. According to me flowline is more easy to operate and also very comfortable. With this angles are easy to achieve whether it low or high angle. It works amazingly well and offers lot of freedom. Shoulder rig is not comfortable for long hour shootings.
