This provides some comparison between Lumi's old and new;http://www.flickr.com/photos/lumicycle/page2/
That's really interesting - the 20w Lumicycle halogen flood is slightly brighter than an 850 lumen Lumicycle LED flood, and a 12w halogen spot about the same as a 600 lumen LED flood. That contradicts both my own experience and what Tazio says. Maybe my existing 12 spot/20 flood system would still be quite bright but the batteries are even more dead than I thought.
This does surprise me, but if it's true it would also contradict the general perception that there have been huge advances in lights - advances yes, but how huge? My Lumicycle originally gave over 4 hours burn time on the 12w spot and weighs 800g. An equivalent genuine 600 lumen Chinese LED (say claiming 900?) that lasted 4 hours would weigh less, but still quite a bit.