Every word of this material reached the page through one man's mouth. Kelley scried; Dee recorded. That arrangement makes the honesty of Edward Kelley a question that cannot be set aside, and it is a genuinely unresolved one rather than a polite gesture toward balance.
The case against him is substantial. Kelley had a criminal record, is generally reported to have lost his ears as a judicial punishment, and habitually wore a close cap. He was a known forger. He was paid well and steadily by Dee, which gave him an obvious motive to keep the sessions productive. He later persuaded Dee, on angelic authority, that the two men should share their wives, an episode that damaged the partnership and that reads badly under any interpretation.
The case is not conclusive. The volume and internal consistency of the material are considerable; the Enochian Calls have a stable vocabulary across separate sessions weeks apart, which is difficult though not impossible to fake under questioning by a scholar as exacting as Dee. Kelley also frequently reported material that displeased him and that he argued against, which is not the behaviour of a straightforward confidence man.
Scholarship has moved. Frances Yates wrote flatly that Kelley was a fraud who deluded his pious master, and Peter French added the possibility of mental illness. More recent historians of Dee, among them Deborah Harkness, Nicholas Clulee, Gyorgy Szonyi and Hakan Hakansson, have largely declined to rule on it, treating the diaries as excellent evidence of what Dee believed and experienced and poor evidence of what was happening in the crystal. Egil Asprem has noted that this leaves a real gap rather than closing one.
The honest position is that the question is open, that it matters, and that the material can be described without settling it.
Sources The Queen's Conjuror: The Science and Magic of Dr. John DeeBenjamin Woolley with John Dee's Conversations with Angels: Cabala, Alchemy, and the End of NatureDeborah E. Harkness, John Dee's Natural Philosophy: Between Science and ReligionNicholas H. Clulee