I'd use Puppet but I'm kinda biased as I wrote a book about it and work there. :) In addition to Rump you can also use Puppet in its apply mode - which is the same as chef-solo. Although Rump wraps some goodness around the process that's worth trying out.
I'd give Puppet a shot here using Rump as a wrap around - you can both use the Puppet DSL OR Ruby DSL (Chef only has a Ruby DSL). It's very easy to create "environments" using Puppet and to integrate a git/CI workflow with your deployments. It's also easy to integrate with Rake tasks or the like.
