Is the open source software a viable alternation to the commercial product?
Open source software are not always free. Some of them can be
commercial software.
In the same way, some freeware are not open source.
The term "Open Source" means the source code can be viewed by
anyone but some open source products should be buy.
Furthermore, a free software is not always a good software. It
depends of your expectation upon the quality product.
Libreoffice or Openoffice are good Microsoft Office-like suite
but the documents they product may be incompatible or have a bad
rendering when opened with the original Office suite.
In general, your question can be answered with a "YES" but then
again, it depends of which Open Source software you are talking
to.