Is there a website, not run by either TfL or this pressure-group, that
gives a balanced list of the pros and cons of this and other projects?

Looking at everything - cost, disruption, environment, etc.?

I think when the congestion zone in West London comes into force next
month, people will be delighted with another zippy way to get around town
that doesn't involve paying £8, and the opposition will quickly dissipate.