The EU gives the UK a chance to compete with the more powerful countries, so I think it's best to remain in the EU.
Brexit would be an economic disaster for the UK. All Brexiters whinge about is sovereignty and immigration. You would think that the UK is being ruled by a theocratic regime. The EU has very little influence on major UK laws, and also David Cameron recently got a deal where the UK parliament can block certain EU legislation. So, I don't get all the fear mongering that is being promulgated by the Brexiters. Also, on immigration: There are more immigrants from outside the EU (188,000) than there from within the EU (184,000) per year, so the whole debate on immigration doesn't add up. It is in itself, a pointless charade.
Thus, the UK should stay in a reformed EU.