The location was Las Vegas. Since attending conferences can be a full-time job, we're finicky about which ones we'll attend. Conference planning is an art and a science, as well as a cottage industry unto itself. If you've been to a well-planned conference, you don't even notice. But if you attend a poorly planned conference, you definitely feel it.
Location is everything.
This is a no-brainer, but it requires a mention anyway. The most popular cities for conferences are the ones that offer things to do at night, which encourages attendance. Pay attention to amenities. Not all hotels are created alike. Go for the hotels that cater to a business clientele.