I can say from using Onshape for a while how that I do not see a big difference in how a part model reacts in my Chrome browser to one running in CAD software on my win 8.1 computer.
I can also say that when I make a change to a part model in my browser that another person that I have shared the project with and is online in OZ can see that change in less time than I can figure. I know this because I was also talking to him on Skype and he verified the change right when I made it.
Dave