Another question is 'What kind of great developer?'. The best developers I've seen in terms of producing awesome technology tend to be quiet, methodical people

Another question is 'What kind of great developer?'. The best developers I've seen in terms of producing awesome technology tend to be quiet, methodical people. They are highly disciplined, and have a routine. This regular, structured way of doing things means that they consistently practice out of hours, commiting regularly to an open source project while mere humans like me flit around playing with new technologies. They develop expertise. Would you want this kind of developer evangelizing your technology? If you sat them with a client, would they have the soft skills to drive the conversation where it needs to go? Would they enjoy, or avoid these parts of their work? I think people are people, and people are different. It's worth recognizing this and looking for the sort of person you need.