The major addition to the 1976 text is a bibliographical supplement updating the publications in the next decade or so, which includes an entertaining account of historiographical disputes by Aidan Clarke, though I think it misses the Ellis / Bradshaw controversy (funny how the memory cheats - I knew Bradshaw well at Cambridge in the late 1980s and would have been sure that the dispute with Ellis was well under way by then, but I guess not). One also misses some of the more recent trends in history - very little about women, not a lot about the life of the poor as opposed to the deeds of the rich, and Brian Ó Cuív's chapter on Irish language is pretty polemical - but it's serious work seriously done.
I found no references at all to my sixteenth century ancestor and namesake, but did spot a few mentions of other relatives. His grandson, also Sir Nicholas White, pops up as a leading Catholic MP in 1634, doing deals with Wentworth (later Strafford). I knew of the family connection with Sir Ignatius White, marquis d'Albeville, who was James II's ambassador in the Hague up to 1688 (remind me, how did that work out?); I hadn't known of a more Belgian link, in that his niece Mary Christina White helped found a Benedictine convent which became known as the Irish Dames of Ypres. I'm also struck that Peter White, schoolmaster and writer in Waterford and Kilkenny in the 1560s and 1570s; Father James White, the Vicar-Apostolic of Waterford in 1604; and slightly more distantly the Jesuit Stephen White of Clonmel (1574-1648) share the surname and roughly the location of the ancestral Whites of Knocktopher and Waterford. And of course it turns out that Sarsfield and the Duke of Berwick were 6x great uncles.
Anyway, it took me quite some time to get through this, but it was well worth it.