I was in Austria recently where 4g is prevalent. It’s fapping great. The maximum I saw was 42Mbps and 22Mbps was probably the average as I travelled about a city.
As other state, the radio network (or last mile) is the limiting factor and this is going to be pretty poor until the rollout is complete. Don’t expect to be able to travel around and pick 4G up everywhere yet. If you want to use it as a fixed line replacement service you might be OK depending on location.
I’d say go for it but don’t trust the coverage checker, make sure you can take it back / refund if the primary location you will be using it turns out to have shite coverage.
My day job is telecoms and have been working with EE for the last 8 months helping them build their new LTE network. They are well ahead of the curve on 4G. Orange and TMUK subscribers will likely be able to roam from the 3G network onto the 4G network and vica versa.
One limitation of 4G at the moment is that to make a voice call you have to disable the 4G data connection and use 3G – so you wouldn’t be able to surf on 4g while talking to someone on the phone. This is just a temporary thing until equipment vendors and operators work out how to do some more complex stuff – like make a phone call 😀