[victor_e]

I'd rather listen to the expert rather than the newbie for a keynote to be honest. Someone who just learned rails should not be doing the keynote.

[davidw]

Hard to say. If the expert has something informative, I'd probably rather read it at my own pace. The newbiew might be more inspirational, or point out flaws that everyone steeped in the system aren't aware of, or otherwise be more interesting. Depends on the people.