SilentPCReview's review, here, says the efficiency is somewhat lower. Nonetheless, their conclusion is "great job".
I've never really understood this "bigger is better" mentality when it comes to PSUs anyhow.
I'd rather use a PSU that has peak efficiency when my computer is working at full load, instead of a 600W+ one when the computer only needs 150W (and mine needs much less than that). 1 kW is ridiculous.