Consensus seems to be that the ZooMed Repti-Sun 5.0 is the better tube.
This is borne out by the tests that UK-based UVGuide did: http://www.uvguide.co.uk/
(take a read through their site - there is lots of interesting information about UV lighting there including bulb fixtures, reflectors, placement)
In my personal experience, I did seem to notice an increase in activity levels in my chams when I switched over to the ZooMed bulbs after originally using ExoTerra. But I can't say whether this really had anything to do with the brand, or whether the former bulbs were simply old and needed replacement. Either way, I've stuck with ZooMed ever since.
Sorry - I didn't realise this was the same question you'd already asked last week. I'm sure some of the other keepers will chime in with basically the same answer.