I have bought 3 regular BB400s and 1 Q3L BB400. That's not a statistically large sample, but my observations may be of use. I don't have an accurate meter, so these impressions are entirely based on careful back-and-forth lighting of white walls.
All 3 BB400s put out about the same amount of light. The Q3L may be a teeny bit brighter, but you wouldn't be able to tell it in normal use. 2 of my regular BB400s are as white as the Q3L. The 3rd is more green, but not in a CMG Reactor sickly way. It's still a fine light - possibly preferable to some since its light is a little more incandescent in appearance.
In the future (these are gifts for family members) I'll probably stick with the regular sandwiches. FWIW I also have a single MadMax module. It's brighter than any of the BB400s, including the Q3L. I really like the MadMaxes, especially since they are cheaper and can be dimmed, and will probably shift my buying pattern to them. They're more efficient too.