For me, it’s the combination of Pandorabots along with AIML that I enjoy. I find the Training Interface invaluable, especially for beginners. In many cases, it prevents you from making mistakes and tells you before it saves the changes.
In most instances, it makes it easy to locate errors, or things you’d like to change. It’s somewhat forgiving, and it frequently produces interesting and unexpected replies. Most of all, I like the tags, and in particular < people > that flips the pronouns, and <srai> that provides an easy link to similar patterns, or patterns you’d like to incorporate in an existing answer. For example, visitors commonly say, “Hi, how are you?” or “Hello, what’s your name?”
I think AIML combines saving time with simplicity.