Haven't used the web gui, so can't comment on it. The core open source ansible product is text-based. A few months ago, I migrated a provision and deploy system from a bundle of fabric and shell scripts to ansible. I'm happy with the results.

Some things are easier to do: builtin templating for things like config files is nice and all the modules I've used work as advertised. Some things are harder: reusing groups of similar tasks is kind of awkward but doable. The main advantage is that the ansible imposes a structure that is necessarily self-descriptive and that makes everything very readable. The docs are great and the learning curve is pretty linear so you can defer messing with advanced features until you need them (at that point you'll probably be happy they exist).