As far as recruiters are concerned, you need to differentiate beween the spiv in a backstreet office with a threadbare carpet, torn plasitc covered sofas, coffee cup rings on a chipped formica desk, and wispy grey tinted, evil smelling air, who takes 'his' teachers to the interviews at the schools in the back of a dented fifteen-year-old Nissan pickup with bald tyres, and the professionals who are also DOS, in-house teacher trainers, and administrators of reputed schools. They are the ones that don't need to plug their wares on websites.
In the past , there have been many attempts at creating blacklists. Blacklists of schools and other employers of teachers, and blacklists of TEFL course providers. Especially, for some reason, in Thailand. Those blacklists either got blacklisted themselves, or were bought off for big bucks by the people they were blacklisting.
There are several dedicated TEFL forums too. This is one. Some are quite different. Some have become nothing more than a closed shop of bar stool banter, ready to bite the head of any newbie who dares to interrupt. Advice from the cynics who are stuck in a rut without a degree in some Asian backstreet cram school on 250 baht per hour, comes in the form of beery expletives and other language you wouldn't normally expect from a teacher. The regular, non commercial posters on TEFL.net welcome serious discussion, and enjoy giving genuine help and advice. We stay neutral because we have to, but we can point you to the interesting threads and allow you to draw your own conclusions. That is not to say nevertheless, that our patience does not get tried sometimes.
However, you'll not find it very easy to get the kind of advice that you are looking for even here. Nearly all posters on TEFL.net are looking for the same kind of advice and they haven't got the answers for you. It is human nature to complain, most of it is righteous indignation, a lot of it is from people who have themselves to blame, but people who are satisfied with their courses generally go off and get a reasonable job, and probably never think of even looking at a forum like this one again. So I'm afraid you're rather stuck with advice from those who either have a course to sell, those who have an axe to grind, or those of us who became recruiters and/or teacher trainers with 30 years of solid classroom/lecture theatre experience around the world.