Yes and no. We have a bridge, so are kind of knocked out of the "real island" category.
But, from what I know from my "real" island friends

:
- You learn to adapt your life to depend on the weather, especially if you are relying on the ferry to deliver you or your goods. (You end up finding mainland friends to stay with, too, because it's inevitable that you will miss the ferry home at least once)
-It is much more expensive, because everything needs to be brought over
-The community is small- so small that one might find it uncomfortable that your neighbors know you- there's no "getting away".
-For those with children, most island school only go to 8th grade- children must "go off" for high school, either attending Gould or MCI (boarding schools) or staying with a friend/relative on the main for 4 years.
-Many island communities are at odds because the people who are paying $$$ for their "cottages" do not like to look at "fishermen mess", and are attempting to drive the commercial fishermen out of the area. On many of the Southern Maine islands, there is little or no commercial fishing activity any longer because the fishermen cannot afford to live there and/or have water access.
BUT....
There are also many, many good things about living on an island- most of them stem from the incredible sense of community that happens on an island.