The difference between 3G & 4G both in speed and latency is profound, and nobody seems to design with 3G in mind, so I find from a data standpoint 3G is practically worse than nothing these days.
All of your apps will say "I have data access!" and send a million requests for tens of megabytes, which will never finish, melting your battery as it waits on timeouts and completely choking the access you do have preventing you from doing anything useful.
