I have a few of both, of different varieties. I just checked the n3, with two powerex nimh against the g2 with a nickel zinc, and the g2 is a bit brighter while the n3 has a longer throw -- but the cells may not be fully charged. I'd say they (both Q5s) are pretty close to each other. I usually grab the warm white versions since I prefer the tints (the WW g2 is my 'bright' edc for around the house and yard).
These are such good buys one can have a whole collection of different Romisens -- one of each of those which Shiningbeam sells. I have the P4 from DX also -- good light, although not as bright as the Q5, and I have mine sitting by the back door, with the Q5 by the front. I have a 2-level n3 from Sb, and it's not bad but the levels are aren't all that different -- I'd guess about the same difference as between the Q5 and P4. Nothing measured here -- just subjective guesstimates -- but they all in the same 'ball park'. I also have a couple of flood-to-throw -- and I don't regret buying any of them.