See this graph of total resources gained over time 25% Vs 33% hold
[img][url=[url= https://docs.google.com/open?id=0B639-f4MLsHEeFppZ1QtWjJMc3c] https://docs.google.com/open?id=0B639-f4MLsHEeFppZ1QtWjJMc3c[/url]] [url= https://docs.google.com/open?id=0B639-f4MLsHEeFppZ1QtWjJMc3c] https://docs.google.com/open?id=0B639-f4MLsHEeFppZ1QtWjJMc3c[/url][/url][/img]
As you can see the total resources are virtually the same at the end of the time period.
What is better about the 33% is that (prior to filling to 100% when it has sufficient pop in orbit) it gets more resources earlier.

Please note this is not the complete picture because it assumes you treat each world as an individual and dont move pop around (more on this later)