Question for the UKers. Do cultural or immigration concerns play a role for you?
I suspect a BREXIT would result in a short economic downturn, but nothing worse. Other peripheral countries seem to do well enough without joining.
I think the economic case is probably the clearest, definitely bad for the UK economy to leave, the question is whether it's a permanent thing or just temporary. Scotland will almost certainly leave the UK and join the EU if we vote out and the knock-on effect for Northern Ireland would be complicated, so quite a lot of collateral damage to our neighbours.
Immigration concerns are at the root of a lot of the "Leave" voters concerns, I think. Bottom line is, we have more jobs than people to do them and much of Europe has very high unemployment, so inevitably people move to Britain. Depends on where you are, but round here, you won't have many British people doing work in pubs/restaurants, care homes for the elderly, building sites, office cleaning, supermarkets, food (meat/veg) processing. Where I work (very well paid high-tech), about a third of people in the office are from other EU countries. Some people (e.g. landlords or indeed people who benefit from house price rises) have done very well out of this, other people have suffered as a result (the unskilled I guess and arguably young people priced out of housing market.)
The "peripheral" countries pretty much have to go along with EU rules anyway (and pay money to the EU in the process), but don't have any influence. Norway is rich because lots of oil/not many people, the Swiss get to look after the money of the world's corrupt dictators, organised crime, tax evaders etc. Neither of those options really work for the UK.
Interesting to look at European Newspapers - the Irish & Germans appear to be pretty worried and begging us to stay; the French commentators appear to relish the prospect of us finally going. Marine Le Pen in France and AfD in Germany both doing well in the polls, so it may not be just Britain that goes through this.