I am a fan of the Venetian, but not Palazzo. It feels like a big Indian casino tent on the main floor. You can see from one end of the place to the other! So much for ambiance.
The shopping at Venetian/Palazzo is very good for high-end items. A great place to window shop if you are not in the market for million-dollar cuff links.
The Palazzo was home to the 40/40 club, but they ran that out pretty quickly. Now, it is setup as a celebrity chef's location. I cannot recall exactly what it is. The Lamborghini dealership is fun, for a minute. Vegas is the only place where they charge people to look at cars for sale. If you don't want to pay, the other option is to eat at the Dal Toro cafe and see the cars for free. Having eaten there, I can tell you that you are better off paying to see the cars if that is what you want to do.
All in all, a flop in my opinion. If it wasn't for the fact that the Venetian is such a hit, and the Palazzo is sandwiched between Venetian and Wynn (another hit), it would have closed already.