I was correct in saying there would shortly be a new beta, but it is not 10.13 it is 10.12.4. So far the only significant new feature I have found is Night Shift has been added to System Preferences > Displays. It is a feature that has been available on iOS for a while now and is belatedly making its way to MacOS.

Originally Posted By: Apple
Night Shift automatically shifts the colors of your display to the warmer end of the color spectrum after dark. This may help you get a better night's sleep.

So far I have only found one glitch, in one application, MoneyDance, the printing is broken. Hit print in the print dialogue and the app hangs reliably every time.

If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein