Vegas is likely going to be more expensive overall, especially when it comes to venues and potentially hotels depending on when you book. Phoenix can be more spread out, so transportation is key. While Vegas has the Strip, which is walkable, getting to other parts of the city can still require taxis/rideshares. Look into specific venue costs and transportation options (like the light rail in Phoenix) to get a clearer picture. Also, consider what kind of 'going out' your attendees prefer. Vegas is known for clubs and high-end experiences, while Phoenix might offer a more laid-back bar scene.