Steve,
For us it is all about business. We actually don’t see Expo as much more than just a trade show, so our ability to succeed business-wise in the environment is what is most important.
The main advantages of Denver:
Great mass transit, making it easy to stay out of town at nice $49 hotels, but stil be 10 minutes from the show.
Tons of great restaurants witiin .5 miles of the Convention Center
Very ‘square’ venue so walking distances are short
Clean, safe environment after hours
Central location in the country, making it an easy trip for just about anyone
Cheap airfares
The only distadvantage I know of is the distance to the airport, but even that isn’t any worse than any other airport.