And using the script or the data load editor depends on the way you want to build your model.
If you want Qlik to do things for you, help you with the modelisation, create auto-calendar, do cross tables, create geoFields, use the data load editor (you need to prepare data for that before loading)
If you want to have full control of your data structuring and modeling, use the script.
You can use both; load editor than unlock to change it within the script.
But, as I said, I think It's the same Oracle connector in both cases.