Hi guys,
My first post on here but must admit have been using MacRumors for advice over the last couple of years!
I exchanged my IP4 today as although not as bad as some have mentioned, it wasn't anyway near what Apple have advertised.
I went through the following -
5 full cycle recharges.
Complete restore of the phone as new (originally restored from back up).
Complete restore of the phone as new from a reinstalled iTunes (recommened by the Genius Bar assistant).
As a test I restored my IP4 and 3GS, updated my 3GS to OS4 and charged both 100% before going to bed.
Woke up in the morning to find my IP4 at 90% after 6 hours standby, with my 3GS at 97%. By the afternoon (12 hours standby), my IP4 was 75% and my 3GS at 90%. (zero useage, although admittedly it was showing up as a few minutes where I've pressed the home button to check the battery!).
Credit to Apple that the exchange was straightforward, lets hope this one is as good as some of the others out there!