Chris, quoting from one of the comments under that article "Could that have anything to do with the constant misinformation bordering on abuse heaped on the free schools by some politicians and some parts of the media for their own biased reasons, not caring about the impact on the hard working teachers, parents and community governors trying to do something for local children?".
Yes, the policy has had some deep issues, but many of the schools will be popular and successful and therefore its unwise to treat them as a homogenous group. There are sometimes threads on the national Mumsnet site started by people wondering whether to accept a place at "a free school" for their child, and often people responding negatively without asking which?, or where? or in what context? etc.
However, one of the most recent ones did get some helpful responses, including this one which just about sums it up ....
Steview "Maintained secondary schools - get their money via the local education authority; have to teach the national curriculum; have to stick to national pay scales for teachers; get OFSTED inspected
Converter Academies - schools that have previously been judged as effective and have chosen to break away from the local authority (some very effective schools choose to stay as maintained schools); get the money direct from government; can deviate from the national curriculum (many don't); can have own pay scales (many don't); get OFSTED inspected.
Sponsored Academies - schools that have previously been judged as poor and have been taken out of local authority control and into the control of a 'sponsor' who receives the money from the Government and passes it to the school; some sponsored academies are parts of 'chains'; can deviate from the national curriculum (many don't); can have own pay scales (many don't); get OFSTED inspected.
Free schools - school set up by local group (sometimes parents, sometimes another local school, sometimes an academy chain) with funding from the government; get the money direct from government; can deviate from the national curriculum (many don't); can have own pay scales (many don't); get OFSTED inspected.
The honest answer is that there are Great, Good and poor schools of all these types - you can't read anything of substance about the quality of the school from it's type."