I have an iPad Mini Cellular (which can run on 4G/LTE) I had previously been using a '3' simcard which runs on HSDPA-DC which is pretty fast, but when this arrived and i put it in, i was amazed as to how much faster it was! I was getting download speeds of 59Mbps!!
I live in london and we get 4G here but it also switches to 3G if i am not in a 4G area and to be fair EE support HSDPA-DC so when on 3G it is also fairly quick.... but once you have a taste of 4G/LTE... there is no going back!
if you register on [...] then it will tell you how much of the data you have used and how much you have left.