Object Loader and
Simple Data Loader allow you to load data into empty feature classes or feature classes that already contain data.
The Simple Data Loader also allows you to load into stand-alone tables.
While the Object Loader and Simple Data Loader are similar loading wizards, the Object Loader provides the following functionality that the Simple Data Loader does not have:
Because the Object Loader loads data during an edit session in ArcMap, once you've finished loading, you can undo the changes if
If the feature coordinates you're loading are not precisely located, you can choose to honor the current snapping environment,
snapping coordinates as they load.
If you're loading into a feature class that has validation rules, such as attribute domain or geometric network connectivity rules, you
can validate the features added and create a selection of the loaded
features that are in violation of these rules.
With the Object Loader, you can load into feature classes in a geometric network, feature classes in a relationship with messaging,
or feature classes that have feature-linked annotation. You cannot
load into these types of feature classes with the Simple Data Loader.
Append geoprocessing tool. This is useful if loading data is going to be used as part of a batch process, but generally the above methods are better for all other occasions