We have stayed in 6606. It is a nice room. We did not share the cabin 6604. The HUGE disadvantage was; the "person" in 6604 was smoking and it was billowing into our room. The security, stateroom, and guest services managers visited the woman every day. She knew that there were people in the next cabin with Asthma but she continued to smoke IN THE ROOM. It got real old for 14 days... Bring a role of duct tape. It reduced the smoke a lot. It's better to have it and not need it.
Other than that, it was great. To the left side of the veranda is a bulkhead of the shp. The disadvantage is one wall os slightly rounded (not a big deal to us). The plus side is, it is a bit more private (the people on the next veranda can't lean over).
Would we stay in 6606 again? YES.