I know its not the direct comparison you wanted, but food for thought?
I had the
MK5 Ibiza LED DRL & AFS Bi-Xenon headlights and now have the
MK3 Leon with LED's.
The
Ibiza had very bright xenon bulbs, however I always felt the auto-levelling set them too low, so much so, I took it to a dealer who put it on the beam tester and said it was fine. I wouldn't call lighting a few foot in front of the bonnet fine, but hey-ho!
Now I have the Leon, and the LED's seem much brighter. But I put this down purely to just being able to see more of the light. On the Leon they aren't aimed solely at a few foot in front of the car like my
Ibiza was.
One thing I do miss is the AFS though, the
Ibiza lights used to turn with the steering, I'm surprised at just how handy (and effective) this was.
I haven't been on an entirely unlit road yet (only picked Leon up on Friday) so have yet to see how the Leon LED's perform on full beam in total darkness. However I have suspicion this is where the big difference will be, the LED's will have a very focused and sharp cut-off I reckon. Whereas the
Ibiza on full-beam was like having light canons on front of the car! Everything and anything was lit up with no dark patches or cut-off. Doubt the LED's will perform like that...