Positives:
House prices are quite cheap, that's definitely a plus if you are selling a house in a more expensive area. If you have a decent budget you can get a massive house, probably with amazing views
Winter is a great time in that it's quiet, not as many things are shut as people are saying, you can still go to the pub!
The scenery is beautiful, a good variety as well in that there are countryside bits as well as coastal. If you love walking its absolutely perfect, there are some countryside walks on the downs with breathtaking views across the island, that are almost never busy. The beaches are great too!
Because it's touristy, there's lots of things to do in the summer, events and fetes and festivals etc.
Generally crime and such seems lower than parts of the mainland, although there are the usual issues that everywhere has
Negatives:
It's a real pain getting back across to the mainland, and expensive. Having to sit an hour on the car ferry and sometimes pay hundreds of pounds for a return ticket is annoying.
The roads can be awful, lots of potholes. In summer they get clogged up and it can take hours to get from one side to the other even though it is a short journey in miles. All drivers seem to either be old and going about 30mph, or young and speeding/dangerously overtaking said old people.
Everyone knows everyone. They will have all grown up together, as did their parents, as did their grandparents.
In summer certain touristy bits will be filled with people, making it a bit of a nightmare trying to go about your daily lives
If you need certain serious medical procedures you will have to go across to Southampton. The main hospital on the island is not performing well, by all accounts