Is deleting in batches likely to save elapsed time?

I frequently have to delete a million+ records from each of several many-million record tables, based on a short indexed field.

SS 2008, SIMPLE recovery model, plenty of disk space, and it doesn't matter if the table is locked for the duration.

The deletes can add several minutes to my ETL process. Would it be worth experimenting with batched deletes in this case, or would the change probably have little effect on elapsed time?