If I were you, I wouldn't wast my upgrade on a phone that is already a year and a half old. If you're goig to use an upgrade, get the 4S. I'm sure there will be a jailbreak available for the 4S sooner or later. About Siri, I use it all the time, and rarely get the can't connect to the network issue. Yes siri does count against your data limit, but it's a really low amount. My usage from my 4 to 4S really isn't any different.
11-15-2011 12:56 PM