The one-volume is handy to have around, especially for communal Divine Office in a parish setting, but it does not include the full texts for the Office of Readings, Daytime Prayer, or many of the Propers of Saints. Priests, religious, and seminarians almost always use the four volume set, which is worth the investment. For those that prefer another English translation, the three volume Divine Office from England is a good choice. I am not familiar with Phyllis Tickle, however.