For the best network, I'd suggest getting a 1 month SIM and testing it in your area. For everyone who might say 'Three sucks', or 'Vodafone is best!', you'll find others who say the opposite.
One network might have better signal in an area, and having "something, anything, even if slow" is better than nothing. Another network might suffer from having good capacity, but also a load of heavy users in a given area, so their network might struggle at 5pm but be faster than anything at 10pm. A user who's never in that area at 5pm won't care. So the best plan is to test it for your own circumstances.
In my own, recent experience:
- Vodafone - Good nationwide coverage. Speeds are quite good if you're stationary. If you have good 4G or 5G from them, it'll likely work & work well. Once you're moving, however, and you'll find that there are gaps in their 4G; previously you'd have dropped to 3G, but now that's been shut down you drop to 2g, where youcan get stuck camped out on EDGE with no meaningful data throughput. In some other places they're a little slow, but nothing too bad. But the trapped-2g situation sometimes means having to constantly cycle airplane mode to get back onto 4G, and that is pretty wearing.
- O2 - Good coverage, but overwhelmed in many places. If you need <= 1mbit, you'll be fine, but as soon as you're at the station and realise you need to search your email for the PDF which has your tickets on them, it'll not be too surprising to find it grind to a halt. They've done good work in London, and are bolstering the other cities, but it's certainly not a network which can bring any kind of fight to EE or Vodafone. My work phone has an o2 SIM in it, and it's fine for that; emails, teams chats, and slack messages make their way through, phone calls are reliable; but I don't need more than this - and so it's perfect for this application. They are getting better though, and so it's really worth testing - you might find they're fine in the places you go.
- Three - So very, very variable. They've piled lots of heavy use customers on, and in many places they've built a fearsome network to match. I saw a speed test of 700mbit on their 5G. But, then, you'll go round the corner and find yourself connected to a 4G only mast which is on its knees, sobbing, begging for respite, and the performance slumps into the dumps. If it works well where you are, it's fantastic. So if your home, workplace, social locations etc are well covered, that's great. But if you're travelling round the country, you are (like with o2) sometimes rolling the dice! For me, however, my main problem is that if you start to get too far into the green bits (Peaks, Lakes, Wales, North of Scotland), they seem to be one of the first networks you'll lose.
- EE - Overall, the most likely to have coverage, and very good speeds. If you aren't constantly jabbing at Speedtest, and are just using your phone, it'll likely "just work". Open Netflix, it'll play. Tether a laptop, you'll have decent fast internet. Sure, there might be places where there are no signal, but I find that with EE as my main network, it's normally me that's still got signal when other networks don't.
Now, there's no real "best" network for everyone. For someone who's 99% of the time in London, they might find that Three always has fearsome speeds & cheap deals - why shop around? But someone pounding the motorways might prefer o2 or vodafone for coverage. My experience is that: if you're in any location, and you need to pick a network which is likely to provide some data, EE is likely to be the one which does. Sure, there are places it doesn't, and the competition really isn't that far behind them, but those are my findings!
The SIMs I'd suggest getting to try each network are:
- EE: 1pmobile. 1 month contracts, full speed.
- Vodafone: Voxi. 1 month contracts, full speed, generous data allowances.
- 3: Smarty. Same as above
- o2: Er.. trickier. Giffgaff is a bit slow performance-wise; they're good for testing "Do I have coverage?", but speed testing on GG is not necessarily indicative of what you'd get if you were to get a SIM from Tesco/Sky/o2.
www.esim.net
