I recall a forum thread a while back in which (besides carrying on the eternal debate about the pros and cons of RM and RF), it was said that Alamy prefers RF because this is increasingly what clients want. This has stayed at the back of my mind, and I thought it should be possible to test how true this is by counting the number of searches in Alamy Measures that specify RM and RF. AM appears not to provide any information other than the search terms on all-of-Alamy searches, so I went to my own most important pseudonym and looked up searches from 1st January to 30th June this year. I stopped counting after 100 pages of search results. Here are the results:
Searches that specify RM or RF
RM: 25 searches
RF: 14 searches
Distribution of RM and RF in pseudonym
The results should be treated with a lot of caution. First of all, number of searches that specify RM or RF is very small and more data might change the picture. Secondly, most of the images under this pseudonym are RM and this probably skews the results. I used only one pseudonym because my pseudonyms aren't subject-exclusive so a lot of searches show up in more than one. Thirdly, results are also likely to vary by subject matter.
But if more forum members were willing to chip in with their own figures, we might build up a more general picture.