I think this is all subjective - I have EE and Vodafone and 99/100 EE will be faster and better even when they both say 4G. This is across the UK given I travel a fair amount.

Where EE falls over is when it does lose reception it kind of just stops everything whereas the Voda will tend to revert to GPRS and you can still get on a webpage.

When I had 3 they were terrible for me in terms of reception anywhere outside an urban area.