What parts of ArcGIS 9.3 Geoprocessor Programming Model diagram are not relevant for ArcGIS 10?
The geoprocessor programming model was an excellent tool for python scripting using ArcGIS 9.3. There is still no equivalent diagram for ArcGIS 10 - although there is a request on the ArcGIS ideas site.
Does ArcGIS 10 have a Geoprocessor Programming Model by using Arcpy? asked if the 9.3 diagram is good to use for ArcGIS 10. The answer was that some of it is relevant and it is best not to use it. However, I really like the diagram and would like to reference it when scripting ArcGIS 10. Therefore my specific question is:
What parts of the ArcGIS 9.3 diagram are not relevant to ArcGIS 10? Correct me if I'm wrong, but from what I understand, if an equivalent diagram was made for ArcGIS 10, there would be new functions added to the diagram; the diagram would only get bigger.
The main differences between arcgisscripting and arcpy, are instantiation and a more rigid adherence to a naming convention, i.e. [tool_name]_[category](*args, **kwargs)
Apart from that the answer from Dan Patterson is correct, you'll have to look at each tool to determine if the functionality or parameters have changed for each tool.
ArcPy is an elaborate stub for COM objects. Using a COM library from python has the added overhead of translating python data types to c/c++ data types. And often requires some complex conversions. Being aware of this, and having an understanding of COM will help you squeeze performance out of your scripts where necessary.