I can confirm the above, at least during the earlier stages of ME. It was CIPL-only, took a while for it to get a version that would work on later models, etc.
That's not to say the guy doesn't know what he's doing, but he initially made the ME series for himself and other devs for experimentation, he ported a couple of plugins to 6.x and such.
Compare it to PRO, which is focused on standard users.
I guess ME would be like a bleeding-edge repository linux distro, while PRO is like a current-year version of ubuntu?