Well the AI prices at Dreams are so much higher than at the Riu, and I'm trying to keep the costs down for our guests (plus the cheaper it is, the more friends will be able to attend). Plus I've also heard that the Riu is a bit more of a party place than Dreams (I've been to the Riu and had a great time, but I haven't been to Dreams yet), and our guests will definitely be filled with partiers. If I could get Dreams for the same/similar price as the Riu for my guests, I would definitely consider it!
You're right though...$85 per guest might add up to $4500 quicker than I think! Hmmmm....