Unbeknownst to many, Westcott and Hort published an Introduction (amazon.com) as a second volume to their epochal edition of the Greek New Testament. The Introduction (amazon.com) has a massively detailed description of their text-critical method (330 pages!). It is, essentially, them showing their work. (Oh that other editions ... you know which one(s) I'm talking about ... would follow their lead!)

Another component of the Introduction (amazon.com) is the first Appendix, "Notes on Select Readings", 142 pages of text-critical notes and discussion on problematic readings. Think of it as the precursor to Metzger's Textual Commentary (amazon.com).

I've never read the two (Metzger and WH) against each other. So imagine my surprise when I read the note for 1Ti 5.19 in both, I added the bold:

Westcott-Hort

v 19 ἐκτὸς ... μαρτύρων ] < Latin MSS known to Hier; also apparently Cyp Ambst, who quote no further than παραδέχου; not D2 r nor (<ἐπὶ) G3.

Metzger

5.19     ἐκτὸς εἰ μὴ ἐπὶ δύο ἢ τριῶν μαρτύρων
These words, found in all extant manuscripts of the passage, were absent from some Latin manuscripts known to Jerome, and perhaps also from the copies used by Cyprian and Ambrosiaster, who quote no farther than παραδέχου.

I'm not accusing anyone of plagiarism; I would be surprised if Metzger hadn't consulted WH in writing his volume. This just surprised me.