With the introduction of 3G, and especially 4G, mobile Internet access is no longer considered inferior to home broadband. In fact, in certain locations, it can actually be much faster than many residential DSL plans.
That said, as you roam around, even within one city like the case of the iPhone 4S, you'll experience changes in connection speed and coverage. That's just the nature of any cellular data connection.
Generally, it's best to use a 4G connection. However, since, for now, none of the wireless providers can guarantee the availability of 4G coverage throughout the U.S., … Read more