Greetings
Mike this is a question to which everybody will have a different answer. I personally find the aggression of the two razors very similar perhaps the ER 1924 is a little more aggressive.
As to which is best again it is do you prefer lamb or beef? For me there is not a scrap of doubt in my mind, I genuinely believe the GEM OCMM the best shaving safety razor ever made, others will disagree.
One of the plus points with all three of the Micromatics is that the head (frame) size is relatively small and neat, this is especially so compared with the head of the 1924 which is big and 'meaty' I find this makes a more manoeuvrable razor and the TTO actions on the Micromatics are the original TTO razors and have never been beaten for reliability and ease of use.
Why don't I send you my spare OCMM and you can make up your own mind.
Regards
Dick.