Some might or might NOT know this but, I did confirm from a MS website that we CAN upgrade from the 8.1 preview to the 8.1
preview RTM BUT at the cost of losing our applications we installed.
I'm not a guy "in the know" and just wanted to share that, if you wait and use Win8 RTM, you can install 8.1RTM without losing your applications. However, if you, like myself, have updated to the windows 8.1 preview and then later install the windows 8.1 RTM, you WILL lose the applications and programs you installed. not sure why but I wanted to give others like myself a little heads up.
I'm optimistic about 8.1.