According to some German newspapers, Britain would suffer because they would still need to do trade with the continent but would no longer have any influence over EU politics and trade laws and such. However, Britain would also regain some form of independence and control about where its money is being spent.
To me the EU has become the one thing it didn't set out to be: a union where money is sunk into countries that couldn't handle the Euro. Greece is a bottomless pit that goes through money faster than a drunk in vegas. Most of the southern countries aren't doing too well either. And instead of having to stand on their own feet there are a lot of countries that are quite happy to receive money from the EU for... not taking any refugees for example. But don't worry, we just give 3 billion Euros to Turkey so they keep all the refugees, and maybe even let them join the EU too, even though two *very* different ideals are going to collide, and one of them doesn't take prisoners (or is tolerant in any way whatsoever).
Also, the administration in Brussels seems like a giant waste of time and money. And why go to Brussels in the first place? There are much cheaper cities to live and work in than Brussels. And at least for Germany is was almost always the case that only politicians that could no longer "make it at home" were sent to Brussels. Basically people that nobody wanted around anymore but somehow nobody had the heart to tell them, so instead they are sent on a permanent and well paid "vacation".
And what do the people in Brussels usually come up with? Some bullshit regulations that interfers with national law and therefore has to go in front of multiple courts, which costs money, the tax payer's money. Also, drafting these regulations also costs a lot of time and therefore money (because people want to get paid), and guess whose money that is? Yep, the tax payer once again...
So by all means, if Britain feels like leaving the EU, who can really blame them? It's not like things have gone wrong over night. It's been like this for years. Too many weak members that couldn't carry the Euro (or themself, for that matter), too much regulation and too much crazy money spending.
I know that I still benefit from the well-being of the EU, but it's also nice to live in a country that still has some resemblance of independence. Granted, due to the Schengen-contract, Switzerland is affected by some EU legislations, but by far not as bad as some other countries. And I never got the feeling of "hey, this guy is giving away my money", because, well, you don't really pay that much tax here (and somehow, the country is still going and actually doing quite well, partly because money doesn't have to be wasted on paying up old loans and interest).
