updating all files on AWS EC2

I'm trying to determine the "best" way for a small company to keep web app EC2 instances in sync with current files while using autoscaling.

From my research, CloudFormation, Chef, Puppet, OpsWorks, and others seem like the tools to do so. All of them seem to have a decent learning curve, so I am hoping someone can point me in the right direction and I'll learn one.

The initial setup I am after is:

• Route53


• 1x Load Balancer


• 2x EC2 (different AZ) - Apache/PHP


• 1x ElastiCache Redis


• 2x EC2 (different AZ) w/ MySQL


• Email thru Google Apps


• Customer File/Image Storage via S3


• CloudFront for CDN

The only major challenge I can see is versioning/syncing the web/app server. We're small now, so I could probably just manually update the EBS or even using rsync, but I would rather automate it and be setup for autoscaling.