Control What?
Borders & Immigration seem to be the hottest topic.
Borders?
The UK is already out of the Shengan Zone, so to get into the UK you have to prove who you are by getting your passport checked at border posts such as Airports, Seaports & Eurostar Rail terminals.
Immigration?
As a European citizen you are entitled to receive anything in your new country that your new fellow country person receives.
For Example: In Spain you cannot claim any money without first paying into the system of Spain and you cannot claim more than you have paid in.
Whereas the UK system is you can claim (pretty much ongoing) benefits as long as you have paid in for 16 weeks.
What the UK has proposed is that EU foreigners have to be in the UK for 4 years, before they can claim any benefits, which seems fair enough in the UK but outside the UK is deemed racist against the free movement of European citizens.
Plus the amount coming into the UK seems 50/50 from free movement EU citizens to outside EU citizens who have to apply for visas.
http://www.bbc.com/news/uk-politics-eu-referendum-36382199 - "The most recent official figures put net migration from EU countries at 184,000 a year and non-EU at 188,000"
Living in the canaries we are outside the EU for Tax purposes, so you come on holiday here you are only entitled to Duty Free Allowances, unlike mainland Spain, (& other holiday destinations such France, Italy, Greece, Cyprus, Malta & Portugal), where you can fill your suitcase with as much fags and booze as you want.
Post from the UK, take between 1 week and 6 weeks, because it sits in Madrid and Las Palmas Customs offices for ages - exactly the same amount of time from China. Again due to being out of the European Tax Zone.
Currently I am waiting for my voting papers sent 3 1/2 weeks ago from North Warwickshire Borough Council.
Also if the UK pull out and in the future want to go back, one of the conditions of (re-)entering, is that the UK would lose the pound.
Prior to 1993 (When the EEC changed to the EU) I was a lorry driver, driving abroad was a nightmare, queuing at EVERY border crossing for hours waiting for your paper work to be checked, then having some 'bullshit' tax "No Pay - No Entry" added, trying different routes to avoid driving for 30 minutes through Luxembourg, but queuing for hours to get in and back out. Currency - driving through countries and having to find 20 Belgium centimes to go to the bog, only being able to change notes and being stuck with £5 worth of change from each country such as France, Belgium & Luxembourg before you got into Germany for example. Getting you goods cleared for custums could take several hours on one occasion it took me 3 days.
Driving through Europe today as a lorry driver is an absolute pleasure, virtually hassle free.