I've been working on a similar but different solution at http://impromptudo.com . I'm currently focusing on quantity and breadth, saving quality and depth for later. Edit: checked out your project, looks very similar to http://usehipster.com , which was recently acquired (?) and it hasn't even launched. So, theres confirmation of the idea.
I've looked at Hipster and don't think their solution is stellar. It's more of Q&A for location which I think is too far away from a city guide. City guides just need a quick web 2.0 uplift in my opinion.