TripAdvisor? They charge for advertising/sponsored positioning, but it's free to claim your business and it allows you to respond to people but pretty sure not do 'moderation' like that.

Google Maps?

I find this is generally region-specific, as what review sites are most commonly used will differ somewhat from region to region.

I have found it preferable to visit the restaurant in question, look around, read the menu, and decide based on those cues around me whether it's worth risking a meal there.

Yelp has become useless, and TripAdvisor is as bad if not worse. The reviews on Google Maps are wholly unreliable as well.

If you're in UK look at Harden's http://www.hardens.com/