It's worth mentioning that any mics based on the Primo EM272 are quite inferior to any using the EM27
3, because the 272 has the FET source internally tied to ground, rendering it impossible to bias it optimally.
Even mics based on the 3-terminal EM273 won't sound as good as the Line Audio CM4, as they do extensive culling and do modifications to the capsule itself that greatly increases it's performance. This has been verified by
@kingkorg who has dug into them and found that no simple DIY mods can get the little Primos to sound as good as the CM4.
This is, of course, also true of the Line Audio CM4 which uses the Primo EM200.