The question resolves to "how accurate are the earliest sources"?

Hadith traditions -- and secular history-- tend to prefer sources closer to the events, but anyone who wants to understand Muhammad and his world has to understand that the description of his life was a matter of intense political and religious importance at the time these were written. There's no contemporary neutral commentator-- we wish there were, but there isn't

So you're left piecing together a "most plausible scenario" from the accounts that are given, reckoning with the [un]reliability of the historians, and each and every historical point needs a careful examination, a collation of all sources, and a judgment call as to what seems most likely. These judgement calls are made all the time by Muslim scholars and secular scholars of Islam, and there are challenges both within methodologies and between them.

Now with respect to Ling, there are scholars in the field who find fault with his readings. Montgomery Watt -- author of the well regarded Mohammad: Prophet and Statesman (the book I normally recommend) had this to say about Ling:

This is best described as a work of piety rather than of critical history. The aim of the author is to present a continuous and detailed narrative of the life of the Prophet, and this he does in eminently readable English. As the subtitle claims, the work is based on the earliest sources; but these are simply accepted and there is no discussion of their value. The author even includes accounts of miraculous events which are altogether secondary to the main story. There is also no discussion of those matters for which there are variant accounts in the earliest sources. Usually he takes the most widely accepted view, such as the view that the earliest revelation was the beginning of Surat al-'Alaq (96. 1-5), and does not mention the variants.

{snip}

Once the character of the work is understood,the author must be given the highest praise for the narrative skill and literary charm with which he has carried out the task he set himself. The reader is carried on from incident to incident. On the author's broad canvas there are dozens of characters, but he manages to let them stand out as individuals. From the numerous events described one gets a feeling of what life must have been like in Mecca and Medina at the time. While the book is intended primarily for 'the ordinary Muslim', it will also enable the non-Muslim reader to form some idea of how Muhammad is seen by Muslims.

Reviewed Work(s): Muhammad: His Life Based on the Earliest Sources by Martin Lings

Review by: W. Montgomery Watt

Source: Religious Studies, Vol. 20, No. 3 (Sep., 1984), pp. 504-505

So that's one learned response to Lings, there are others which are more complimentary.

Asma Afsaruddin at Harvard said

It is admittedly difficult to find a gift for narration wedded to impeccable scholar ship, but Martin Lings may be said to have achieved this rare combination. The drama inherent in the events that led to the establishment of Islam in the Arabian peninsula in the 7th century provides momentum in the telling and retelling of the sfra, the biography of the Prophet Muhammad. But to provide the verve and the magical cast that invests each retelling with a fresh vibrancy—even for the reader who knows the events well—can only be the accomplishment of a gifted racon teur. Martin Lings is that and more. All those who have ventured to translate the Arabic language into English and have struggled to render its idioms and nuances into comprehensible English will find this work a literary tour de force.

Reviewed Work(s): Muhammad: His Life Based on the Earliest Sources by Martin Lings

Review by: Asma Afsaruddin

Source: Middle East Studies Association Bulletin, Vol. 30, No. 1 (July 1996), p. 65

And Khalid Yahya (Temple University)

In the end, the result is something of a mixture. Ling's version, though adhering to Islamic tradition, cannot be called an authoritative Islamic one, because many of his selections would be disputed by at least some Muslims. Thus, his claim that al-'Abbiis heard the dying Abu Talid become a Muslim (p. 97) would be denied by many. On the scholarly plane, his harmonization of versions of widely varying consistency does not establish the facts. Ling's book is likely to have its greatest appeal on the popular level, especially for English-speaking Muslims who wish to learn about the traditional biography of the Prophet in some detail.

Reviewed Work(s): Muhammad: His Life Based on the Earliest Sources by Martin Lings

Review by: Khalid A. Yahya

Source: Middle East Studies Association Bulletin, Vol. 19, No. 1 (July 1985), pp. 68-69

My two cents worth is that I lean more to Watt-- but you'll find plenty of criticism of that. The one thing that I think everyone will agree on is that the biography of Muhammad is at one time both a sacred subject, and a historical subject, and you approach the story differently depending where you are in that. Lings is essentially approaching Mohammad's story from the sacred point of view -- with exception as noted by Professor Yahya-- and it serves somewhat better as a guide to "what Moslems _believe_ about the life of their Prophet" as opposed to how a secular historian would approach a secular subject.

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