I'm an Ops guy who just happens to write a lot of code, rather than a coder who happens to handle Ops, and I can testify that Rails is not fun to manage, from an Ops perspective.

Setting up a tightly version-controlled, centralized deployment for a full Rails app stack is more difficult than doing the same with J2EE, but this is partially due to the immaturity of the platform -- Ruby, and Rails, just haven't been in the mainstream for anywhere near as long as Java has.