From: John Navas on
<http://ptech.allthingsd.com/20100519/sprint-4g-phone-hits-new-speeds-but-battery-lags/>

However, the data speeds I got in my tests weren�t spectacular, or
anywhere close to the typical maximum Sprint claims, even in
Baltimore, where the company�s 4G network is mature. And, when using
4G, the EVO�s battery runs down alarmingly fast. In my tests, it
didn�t last through a full day with 4G turned on. The carrier, in
fact, is thinking of advising users to turn off the 4G network access
when they don�t think they need it, to save battery life. This
undercuts the whole idea of faster cellular speeds.