Nicole,
Hi! I just got married at Dreams Cabo. I am from PA, so 18 of my family members& friends just flew from PA. My wedding was August 2nd. The flights were about $500.00 per person for round trip. I have never been to Dreams Cancun, but have seen pics and read wonderful reviews. We selected Cabo, since it is more protected from hurricanes. I think they offer direct flights to Cancun from Pittsbugh. My family all flew Delta or Continential to Houston or Atlanta and then to Cabo. It was a nice flight. 3 hours and then 2 and half hours.
If you book early there are deals... we went with August and it was hot, but it is hot in Maryland & PA in August as well! We loved it, PM if you have any questions! Good luck!