Today Logos unwrapped four-volume, 1979-1995, revised International Standard Bible Encyclopedia (ISBE) for $99. Even though its a good deal, I still want to save some $$$. There is big possibility to get ISBE 1915 for $30.
My Question is how different they are? Are they fully revised (100%) of the new conent, or partially?
Would you consider to have both, either one, or none?
Thanks in advance for your suggestion and opinion
PS: I do have AYBD, and IVP (OT and NT) series.