The 5G speeds on three are unbelievable. Nearly all the masts near me are 5G enabled so have amazing 4G too. 4G hits 150mbps in most areas and 5G comfortably does 700mbps. No more of that EE rubbish anymore! I managed to get the unlimited data only sim for £3 a month. I have a dual SIM phone so I use the data only sim for data alongside Sky Mobile for calls and texts. This system works really well alongside the fact my phone has the capability to use the second SIMs data connection as WiFi Calling (Called backup calling on my phone, I believe iPhones can do this to - I'm on a Samsung). Nevertheless, I'm impressed with my 700mbps unlimited everything package for £3 a month!
The deal I used came with 2 unlimited Sims for £6 a month so I stuck the other SIM in my Huawei B535, it does 110-150mbps, I hope to get a 5G router soon so I can get near gigabit for £3!!!!!