I've finally managed to get hold of Bart Ehrman's Whose Word Is It? at a reasonable price (5 quid) and have undertaken a comparison with Misquoting Jesus. It appears that the differences between the two are even smaller than I had previously thought (original differences between the editions mentioned here probably stem from pre-publication drafts). The main differences are the title, subtitle (US: Bible; Britain: New Testament), size of the upside down Hebrew (bigger for Brits) and the blurb on the back cover. The three bullet points of the US edition that focus on the corruption of the KJV, the Pericope Adulterae, and the threats of damnation at the end of Revelation have been removed from the British edition.
Continuum, publishers of Whose Word Is It?, have also brought out the various images rather more crisply.
The pagination is very occasionally different in the two editions, but overwhelmingly pages are typographically identical.
In general typos have been faithfully transmitted from one edition to the other:
scriptuo continua (pp. 48, 90)
Desiderus Erasmus (p. 70)
periblepsis (p. 91 bis)
v. 27 [for v. 30] (p. 192)
though 'the Timothy LeHaye and Philip Jenkins series Left Behind' has now been corrected to 'the Timothy LaHaye and Jerry Jenkins series Left Behind' (p. 13).