Is it an exciting city? One full of night life? Great weather?
Or is it a boring one?
It depends on the purpose. If you want high engagement with the audience, the boring city will filter who is coming for the topics vs. who is coming for the vacation.
If the main goal is large turnout, then the excitement of the city becomes more important.
Marketing is a filter. Picking a boring city and adding a long application to make someone have to fill out to attend ensures that only the most engaged are going to show.
After getting a highly engaged audience, the hope is that the conference becomes so great (great people make great conferences) that they come back next year, and tell their friends who are just as excited about the topic as the people that came the year before.
Our world is full of filters, can you see them? Can you apply them?