Norway and Switzerland are in the EEA and Schengen, so it doesn't really matter whether they are in the EU or out of it, they benefit. They have to pay into the EU without any representation though. Not the best deal in my eyes. Note that both have agreed to Schengen, which has dramatically eased

Iceland and Greece have had economic trouble, but because of vastly different reasons (insert any link to Paul Krugman analyses of the European debt crisis here). The Troika is also not a product of the EU, it is a product of the Euro and the lack of a fiscal oversight complementing the monetary oversight (ECB).

Stay in. There is no chance of this kind of stuff happening in the UK because you aren't in the Euro.