Not a huge deal, compared to missing documents and the app not working, but when I logged into the beta (using incognito), I noticed that the Document sidebar is not showing the hierarchy below one level deep. I can see the name of of the document, click the carrots to show the first level. The carrots show next to each element on this level, clicking on them rotates them, but nothing shows. Everything displays fine in the pane.
Other than that, everything seems to be working fine for me. All my boards are there and working (although they were reordered, but rearranging them back, closing the beta and reopening seemed to keep them in the correct order). The app opened up pretty quick (about 4 seconds of the loading documents screen). Changes I make in the beta reflect in the stable and vice versa.
Just FYI: I have 5 documents. two are around 12,500 items each, one is around 1000 items, two are under 200 items each (this does not include the ones in the trash).