[carbon8]

I use chef, but I have no experience with puppet. Overall I'm happy with chef, although there are rough edges. At this point, I can't imagine not using something like chef or puppet.

I found chef to have a bit of a learning curve, especially when running your own chef server. I actually gave up using the server after a while and manage my servers (between 5 and 10, depending on what I'm working on, plus a bunch of one/two-off servers for client work) using chef-solo. Now that they offer a hosted server service, I might start using that, but I'm pretty content with chef-solo, roles and a minimal json config file on each server.

Chef has been a bit of a moving target during its development, so it's been hard to keep up with. This goes both for chef itself (although, presumably the API will be more stable after it hits 1.0) as well as the cookbooks. I kind of dread pulling in the changes from main cookbook repo because it's tough to know whether some change to a cookbook will negatively affect your config.

It doesn't necessarily save time up front; it takes more time to write a bug-free cookbook than do an apt-get install and edit some configs. But over the long run it makes it much easier to understand your server config. Rather than having long-forgotten edits to hidden config files, you have a solid record of exactly what your server config is.