While iPhone 4 adds 3G HSUPA (high speed uploads) to preview HSDPA 7.2 (high speed downloads) and is giving many users much faster data, others are filling our inboxes with complaints their speeds are so slow they border on 2G EDGE... or worse.
I know when I upgraded my iPhone 3GS to iOS 4 I had some data issues but almost immediately my carrier, Rogers, pushed out an OTA (over the air) Carrier Settings Update, taking it from 7.0 to 7.1. After that, I was flying.