Regarding what happened post Russell in 1917, if you ask a JW, they'll say it was the fault of the ousted board members who were 'self willed'. If you ask an ex-JW, they'll say it was a 'power grab' by Rutherford. The latest yearbook elaborates on the situation:
"Shortly before Brother Russell died, he had arranged to
send Johnson to England as one of the organization’s traveling representatives. . . . Sadly, the adulation he received began to warp his judgment, and he became convinced that he should be Broth-
er Russell’s successor.
Without authority, Johnson dismissed some Bethel family members in England who opposed him. He also tried to
seize control of the organization’s bank account in London,
at which point Brother Rutherford recalled him to the United States.
Johnson returned to Brooklyn, but instead of humbly accepting the correction he had been given, he repeatedly
tried to persuade Brother Rutherford to let him return to
England to continue his work there. Failing in this endeavor, Johnson tried to influence the board of directors, four of
whom sided with him. Anticipating that these men would try to seize the organization’s funds in the United States, as Johnson had attempted to do in England, Brother Rutherford acted to remove them from the board of directors. The law required
that each member of the board of directors be elected annually by members of the corporation. However, at the annual meeting of the corporation on January 6, 1917, only
three members of the board, Joseph F. Rutherford, Andrew
N. Pierson, and William E. Van Amburgh, were elected.
They filled the positions of president, vice president, and
secretary-treasurer, respectively. No election was held for
the remaining four positions on the board of directors. The
men who had held those positions, the four opposers, had
been elected to the board in the past, and it was understood by some that they would hold those positions for life.
However, because they had not been reelected at the annual meeting, they were actually not legal members of the
board at all! So in July 1917, Brother Rutherford exercised
his right to appoint four faithful men to fill the vacant board
positions."
Also, one thing I've heard over and over through anti-JW sources is that the Bible Students lost most of their membership to splinter groups. However, the yearbook goes on to say:
"While some Bible Students sided with them
and formed other organizations, the vast majority of the Bible Students stayed faithful"
"the results of a referendum of the congregations,
which were published in The Watch Tower, showed that the
vast majority of the brothers supported Brother Rutherford
and the faithful men at Bethel"
I know there's two sides to every story and I'd like to read more if anybody has info or links. Thanks.