That's a good (and presumably unintentional) demonstration of the problem - the European Union is a hugely complex, very political beast and the right answer to that question depends heavily on your political frame of reference and priorities. Even just the free trade-related aspects can be accurately described either as giving up control of our own laws and regulations to a centralized bureaucracy or enabling trade by removing non-tariff barriers depending on how you want to frame them - since almost all non-tariff barriers other than differences in regulations are banned by WTO rules they're the same thing, one description just emphasises the benefits and the other the downsides. (I've even seen a certain FT writer who insists he's not pro-EU use both framings - the positive one when discussing the EU and the negative one when discussing post-Brexit trade deals outside the EU.)