I've run about a dozen different M30s on a wide variety of cell combinations. Same with M60s and M61s. Nothing does better than the 1500 Elites. They get closer to maximum V-in and have amazing current capability.
I don't bother with measurements. I have enough SF bodies and tails to do side-by-side testing.
In my world, what looks brighter is brighter.
+1 on this. i have an M30 in a vme head/twisty body setup -- love this light, but would also like to see it have a lower mode for longer run time.
I own two M30WF modules. One is driven by two NiZn AA cells, the other by three NiZn AAs in a Fivemega 3xAA body. Eac packs a punch. In the 3xAA, the resulting flood is marginally brighter but essentially equalled by my 3xNiZn Dereelight XP-G + diffuser lens from Flashlightlens.com.I like the 5.5V top range of the M30. One of my favorite setups is an M30 in an old SF with 4x Elite 1500 2/3A cells. At 4.8V, it's the brightest M30 I've seen.