If you’re interested in a no holds barred, knock-down, drag-out, competition of a leading commercial piece of software vs it’s open source counterpart….
You might have to look elsewhere. 
Not to completely disappoint you, but I have written a in-depth whitepaper about the features and abilities of Pentaho Kettle and Microsoft SSIS.
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Microsoft SSIS and Pentaho Kettle:
A Comparative Study for Three-Tier Data Warehouses
Michael L Grecol
Georgia Southern University
Introduction
Extraction, Transformation, and Loading (ETL) tools integrate heterogeneous schemata, extracting, transforming, cleansing, validating, filtering and loading data from sources into a data warehouse[1]. The ETL process and the associated tools may be used in a greatly varied number of situations where data must be cleaned and moved between data sources. The subject of ETL tools is too broad for a whitepaper; therefore, this whitepaper will only cover the use of two ETL tools (Microsoft SSIS and Pentaho Kettle) within the purview of data warehouse design and implementation.