Both shows are very good but are also somewhat different.
Both you get to meet wonderful people, do some networking, conduct some business, meet the sponsors, and all the other things that go along with this business.
Vegas is a bigger show and very spread out over multiple places. If you love a party town with gambling, shows, and non stop action this is the show to go to.It is very spread out so it is a bit difficult to find people. I personally don't like this show as much but that is just me.
Hollywood is smaller and all in one very large very nice hotel. It's fucking hot here in August but the whole show except for the pool parties is indoors in the hotel. It has this huge lobby with huge fake palm trees in it all under glass and I often find myself hanging out here seated at a table just watching people going by. It is a good place to be if you are trying to hookup with people and you don't know where to find them.
At both shows you should try to find the off the showroom stuff like the private parties and hospitality suites as this is really where the good stuff is.
I'm a non smoker with very little tolerance for cigarette smoke and the Hollywood show is mostly non smoking so for me this is the deciding factor to which I'll keep on going to. It also helps that I live about 8 miles from this show. lol