we did the 4 day Dream Aug of 2014, OV for 5 persons for $4650 instead of using our DVc points, which was about the cost of a non-DVC Disney cruise. $4.5K is a lot to pay for a late Aug cruise to the Bahamas, IMHO. Oasis was the same price for 7 days, same week. Teens voted for DVC cruise. Cruise made 2 stops at private island and none at Nassau.
It was soooo worth it! Food was upscaled--lobster night (don't think they usually have that). Normal entertainment, plus they flew in 2 Broadway leads (Mary Poppins and Tarzan) who sang Bway tunes one night--incredible. Mulitple enrichment lectures, like the creators of Big 6 telling us with slide show how they create a show, pitch to execs, editing process (including showing us scenes deleted/rearranged) of Big 6, which had not premiered yet. Man who has done Goofy's voice for 20+ years was the MC of beach games. Engineer of Disneyland rides talked about creation of DL, funny moments, etc. Didn't have time to do everything. Lots of trinkets, goodies each day (DVC scrabble, tumblers, pins, journals, backpacks, etc.)--but I could buy something in the gift shop on a regular cruise instead.
DVC cruise would not be worth it for a young child, regular DCL is fine. My teens liked it a lot, but they went to all of above.
I would not buy direct just to do a DVC cruise and I don't know that I would pay that much $ for the 7 day. But, the 4 day with a weekend added on at DVC to make it 7 days was one of our best cruise/vacations.