There's more than just 3 credit agencies, it's just that those three are the most reliable of them for credit reports. Given all the complications people have with even those three, it really doesn't say much for the rest of the industry.

The odd thing is, I never had to worry about this stuff in the UK. There's no notion of a credit score or centralised credit agencies that I needed to worry about. Most loan etc interactions take place with your existing financial institutions who already have your information on record.