I have noticed in the past - and confirmed yesterday - that the touchscreen response on my iPhone becomes slow to the point of unusable when 4G is enabled and in use. As soon as I switch 4G off in Settings, it returns to normal.
Can anyone think why that would be?
Also, at least on my phone, 4G appears no faster than 3G in the CBD to be honest. It may be technically but for normal email/browsing etc there is no appreciable difference!