What do you mean by "definitive"? I've never heard anyone dispute the authority of Goldberger. One possible flaw compared to Sala is that it "only" has 175 watches or so IIRC, whereas Sala has about 300 + all of the additional references from the archive.
However everything I've heard is that UG until recently was a relatively obscure brand whereas Longines was an industry leader and a giant-- harder to document and sum up I would think.
So in a way, a selection like Goldberger's may well be doing a service of highlighting notable models. It's not as large a sum as AJTT for sure, but I've seen experts note that AJTT contains a number of mistakes regarding Omega military watches for example (I've found one mistake myself), so nothing's ever perfect...