of course I had to test the “Antennagate” myself. So I put a nice little “Death Grip” around my iPhone and watched. What did I see? My iPhone 4 switched from 3G to GPRS. But it did not lose the connection. When already in GPRS it will maybe lose 1 or 2 bars, that´s it.
Did I noticed anything in daily usage? No, not at all. Never dropped a call or went offline.