The vibe.
Macau feels like a place to go for hardcore gambling and high end dining. You just feel like money talks and BS walks. Every gambler feels serious... everyone wants to show off their Gucci and bling watches. You bring 50 thousand USD to gamble and feel like you just brought 300 bucks to Vegas. Families are far and few in between. It's like 75% male. Prostitution almost out in the open (less so nowadays, but the legacy is there). Saunas everywhere and you know what that means. Foot traffic outside the casinos is to just get from one place to the next (casino).
Vegas is just happening. You walk around there's loud music everywhere. Lots of casual gamblers actually having fun even if they are only winning small at the craps table. Lots of foot traffic on the strip where you can see lots of cool things outside. Family friendly. All types of shopping and not just LV and Hermes and Rolex. All types of food and not just fine dining. People actually use the pool!!
Having said all that... Macau is still a cool place to check out. If you plan on gambling, bring at least a few thousand USD cuz the min bets are very high especially on weekends and holidays.