Stay, obviously.
Despite what the 'out' campaigners say, the EU has been the single most important factor in the maintenance of peace in Europe since the end of WWII.
Economically, the UK will be royally effed if it leaves the EU: it will still need to abide by all those regulations that form the backbone of the 'out' argument, otherwise it will not be able to trade with the EU. The global corporations will leave, so goodbye Ford, Toyota, Nissan, Tata, and tens of thousands of jobs, welcome home tens of thousands of expats who no longer qualify to work and/or remain in EU countries.
The idea that leaving the EU will result in the repatriation of democratic powers to the British people is a sad joke when the corporately-owned Tory government has no interest in seeing any such thing as democracy - witness their electoral gerrymandering, hostility to devolution and sad, electioneering lies about decentralisation and the creation of a 'Northern Powerhouse'. Funny how George Osborne hasn't mentioned that since the election, isn't it?
I hate much about the EU - the Christian capitalists' club - and hope to see Schäuble, Dijsselbloem, Merkel and the bunch kicked hard in the nads, but my dislike how the EU is currently operating doesn't make me want to ditch it, but want to change it. It certainly doesn't drive me into the arms of crypto-fascists, ethnic nationalists and corporatist libertarians.