I own the M30, and I once owned the M21. I also have an M20 R2. I sent the M21 back because it was not much of a step up compared to my M20 R2. I couldn't tell much difference in brightness between the two unless I did a ceiling bounce test, so I sent it back. The M21 was more floody than I expected, but I should have known this since it has such a big LED in this small package.
The M30 is my favorite of the 3 by far, but not for EDC (too big for EDC.) The M30 is a big wall of light with more flood than throw but I'd say it has mid-grade throw just because of how bright it is. Even though the M30 is a year old with no improvements, I'd buy it again if I lost mine. I even have an EagleTac M3C4 XM-L mega thrower, but it's a little chunky & doesn't ride well in my pocket. The M30 still gets its fair share of use because it's small enough to ride in my pocket for a while. For a high-powered light it's smaller & slimmer than most in its class.