David Goldman in CNN Money describes the problems with 4G in the US:
You’ve seen the 4G advertisements from T-Mobile, Sprint and Verizon, bragging about a much-better wireless network with blazing fast speeds. Here’s the secret the carriers don’t advertise: 4G is a myth. Like the unicorn, it hasn’t been spotted anywhere in the wild just yet—and won’t be any time in the near future.
The International Telecommunication Union, the global wireless standards-setting organization, determined last month that 4G is defined as a network capable of download speeds of 100 megabits per second (Mbps). That’s fast enough to download an average high-definition movie in about three minutes. None of the new networks the carriers are rolling out meet that standard.
So, when they say 4G, they mean something faster than 3G.