The comment that caught my eye, and really put the whole debate in a nutshell, was this one:
It is vital that our national records are not saved in a format owned by any single company. Ask yourself the question: what would we do if we needed vital documents created on a Wang processor 20 years ago.
Most people reading this will never have heard of Wang (that's the point), but 20 years ago they were where Microsoft is today -- Wang sold desktop computers and word-processing software, and they owned the majority of the word-processing market. Five years later their computers weren't worth their weight in scrap metal, leaving users with a bunch of Wang-format documents that needed to be converted to the format of the new market-leading word processor.