I don't know how to review the Palazzo without it being a comparison to the Venetian. The rooms are newer, look better, and in the suites, the divider between the couches and the beds is a flat counter/bench area which is better and more useful than the rail divider at the Venetian. And I think the counter lights up or something. That's about all the differences I noticed in the suite.
However! I don't think that's enough to make me prefer the Palazzo. It's a beautiful hotel and casino, but I get a better vibe in the Venetian area. Plus, the Grand Lux cafe at Palazzo closes. Not a big fan of Grand Lux, but it just seems like we always end up there late at night when all restaurants are closed... so no matter what, we end up at the Venetian.