In personally think there is much more to do in Rome than in Venice. I think there are three must do's-the Jewish quarter, colosseum and surrounding area and the Vatican. I'm Venice all you need to do us roam around a little and go to Burano
~1 (Don't really agree or disagree
) I think u should spend half your time in each.
Rome: Spanish Steps, Castel Sant'Angelo, Piazza Venezia, Pantheon, Trevi Fountain, Vatican, Colosseum, Jewish Ghetto
Venice: Jewish Ghetto, Ponte di Rialto & Rialto Market, Doge's Palace, Campanille (Bell Tower), Burano, Murano, Ca' d'Oro and of course take the #1 vaporetto up or down the grand canal
Venice to Rome will take u about 2.5 hours if u take a eurostar.