I just installed the beta yesterday and was thrilled with the easy Dropbox integration. However, my 1,299 items over LTE was taking a horrendous amount of time to sync my items for the first time. In fact, the progress bar never made it beyond the D in Dropbox and then an error occurred According to the log, it was a Dropbox error. I made three more attempts which all failed without any update to the log.
Upon returning home hours later, I used my Wi-Fi connection and it worked much better. Still slow, but better.
I am not sure if Dropbox or LTE (which was full bars) was the issue but you may wish to warn users that first time syncs can take some time and to use a stable connection (i.e. don't drive while downloading.