I have been on it. The Dream is the first of the "Dream-class" ships from Carnival, the same size and layout as the newest Carnival ship, "Bliss."
I personally like the Western Caribbean - but its six of one....
Except Dream does not have all the new decor and "Funship 2.0" features of Bliss. The ship is big and tends to get a bit crowded. It's worth dealing with that if you are on Magic or Bliss (the other two similar sized ships) because of the different onboard features, but Dream has not been getting the same reviews as Bliss.
If you get a great deal, though, it is always worth it.
Keep in mind that October is the peak of hurricane season. That may mean you have to change your cruise plans - but very unlikely the cruise will canceled, Most likely if there is a storm they will just change the itinerary (ports of call). As far as weather goes, though, probably the riskiest month of all - would probably be just fine, but always a chance of storms.
Last tip: book a mid-ship lower deck balcony stateroom.
Last tips -