I think the Light Action are marked more for touring and beginners, due to it's ease on knees and its light action to get out. The Zeros allow fine float adjustments. They'll even allow you to limit float in either direction independently, for example: you could have -6* to +4* float, or you could limit the negative and maintain all 15* positive, etc.

I just placed an order on Zero Chrome-Moly pedals with the initions of swapping the spindle out for a titanium version. From my understanding, all pedal bodies are the same. If all Chrome-Moly pedals are imported and SS and Ti are made in the USA, I might have spent the extra cash on the Stainless Steel model...

I have located a really good deal on Speedplays right now, plus an extra 10% off. Shoot me a PM if you would like the link. I paid <$100 for my Chrome Moly Zero pedals. After Ti spindle swap, I'll be below the weight of the stock Ti model and only spent ~$160 (including shipping).