mattur - 3:41 pm on Jun 6, 2011 (gmt 0)
Microformats were created in an open and community-driven way. RDFa was created in an open and community-driven way. Schema.org was not
Note that Microdata was also developed in an open and community-driven way. Schema.org is a just a schema (shared vocabulary) for Microdata.
Manu's main objection appears to be that schema.org uses Microdata instead of RDFa; which is understandable since he's invested a lot of effort into RDFa. But it's not a convincing argument for why schema.org should use RDFa.
The W3C RDFa and W3C Microdata specs are competing technologies. It's a highly politicised issue for the W3C because TimBL invented RDF and then the W3C spent years building a temple around it in the XML years.
RDFa is more powerful but has an history of being misunderstood and mis-coded by authors. Microdata is a bit simpler, and this appears to be the reason it has been chosen over RDFa for schema.org.