Hi tsakumar81,
Both IEnumerable and DataTable are used for handling large amount of data.
But using IEnumerable is more prefferable as you dont have to convert data into the DataTable. It can be used directly.
IEnumerable is much lighwieght than DataTable.
DataTable increases load on processor and time complexity also increases as more time is used to create them and bind data to it.
But again, its upto the requirement for each case.
Using DataTable you can insert data in Bulk with only one single call to the database, without passing multiple paramaters.