I worked at a small Rails shop a long time ago. Everyone had their Mac setup differently (they each did the setup themselves), and nobody really knew how theirs

I worked at a small Rails shop a long time ago. Everyone had their Mac setup differently (they each did the setup themselves), and nobody really knew how theirs was setup. Until something broke. Development domain names - some people used /etc/hosts, some people used pow, others used PassengerPane. For packages, a few people used Brew, some used MacPorts... In the end we went with a standard setup where I implemented things like rvm (we had both Rails 2 and Rails 3 apps). And even created a CentOS setup script which was as similar as possible.