Over on the DON'T LET IT KILL YOU blog, the author is writing a series on using the Holmes rulebook together with the Mentzer DM's book. Here are the entries so far:
Holmentzer Monsters: Intro
Holmentzer Monsters: A-D
Starting with the third entry, he's going through the monster lists in Holmes and Mentzer and comprehensively comparing them (and vis-a-vis Moldvay Basic as well). It's interesting to note the differences in iconic monsters (such as the Carrion Crawler) between editions, and see where the text of the Holmes edition remained essentially the same.