Use gem capybara-webkit instead of Selenium?

[MarkDBlackwell]

Why aren't we using the faster and more normal capybara-webkit instead of Selenium?

I presume (with either) we would be testing Javascript code.

A similar issue exists for Rails Example App rails-prelaunch-signup.

Many Cucumber features are failing (for me) without a Firefox binary installed on my Linux box:

Could not find Firefox binary (os=linux). Make sure Firefox is installed or set the path manually with Selenium::WebDriver::Firefox::Binary.path= (Selenium::WebDriver::Error::WebDriverError)
      ./features/step_definitions/user_steps.rb:144:in `/^I follow the subscribe for silver path$/'