I've starting using Yosemite around the fourth or fifth Developer Preview (one of those was a full installer if I can recall it correctly), am now on Gold Master candidate 3 and had zero problems with it. Works just like a charm, on both my machines. So I will just do an upgrade to the public release build, either via the full installer already available after redeeming the GM code from the Dev Center or via a update, if Apple should release one today or tomorrow. Only thing I did was repair permissions before and after every update.
My point is: if you don't have any problems with the Public Beta, if everything is working as it should be, I don't see the point of doing a clean install unless you just want to start fresh. I only do that when I run into serious problems or when buying a new machine. If it ain't broke, don't fix it. I do know, however, that some people on here will disagree with me on that.