I am prepared to put both for leaving/staying. If I put anything that could be a positive though someone will say its not true or want bibliographies of evidence. What I put is what I believe, I am not perfect but it is done in goodwill.
Another issue is not we only really left 3 months ago so its very early days for any changes.
On the leaving side - we are now free to do own trade deals, over time we will stop giving payments to the EU (£8.6bn per year at last count), UK Government has more flexibility to provide subsidies to internal businesses, we have a more competitive exchange rate, there is no pressure on the UK to joining the Euro or join our monetary and fiscal policies with the EU, we are able to import more freely from non EU countries, we are able to impose conditions on the movement of people into the UK from the EU. We now have the freedom to accept EU laws or reject them on UK affairs, before we had to adopt them. The UK government appears more interested in helping economically deprived regions of the UK and the Tees Valley with significant OK promises at present. (Civil service jobs, Wind Turbine production, Carbon Capture, support for steel manufacturers, infrastructure investment). Some large multinationals have been stopped from moving profits (through dubious charges and transfer pricing) out of the UK for tax purposes to areas of the EU they have done special low tax deals with like Republic of Ireland and Luxembourg. The price of some food stuffs has dropped for example grapes from South Africa in Lidl are now £1.09 used to be more like £1.79 per punnet five years ago I suspect import taxes are now lower. (one of the prime objectives of the EU is to protect EU food producers in this example Spanish grape producers).
I accept its more difficult to export fresh food that highly perishable food as it requires vet checks etc. That small value exports to the EU are not economically viable at present. That some financial services jobs have left or wil leave the City of London (around 0.5%). That EU regional development grants will soon stop. That people can't just hop from their EU homes to the UK homes without any time stay restrictions.