Kickstarter is actually built using Ruby on Rails.
For me, as a PHP developer, would be more ideal and faster to create a similar site using PHP.
I would rather use a popular programming language with a large community, because if you get stuck, you can easily find answers on forums, or in case of hiring a dev. team, it's easier to switch them to another team if things doesn't work out. (believe me, it's quite common with real-world projects)
PM me if you'd like to discuss this further...