Last time I went to San Diego for a business convention, it was horribly expensive. I don't know if that was due to the convention, or if that's just the way it is there. The airfare and hotels at that time (6 years ago autumn) were hands down more than Vegas was this year. If it wasn't for the cost though, I'd agree that San Diego would be a great spot.
The main thing I would want though is a place that is 24/7 and doesn't require vehicles. So for those criteria, Vegas is pretty much the ideal place.