iPhone iOS 4 and Battery Life

Since upgrading to iPhone OS 4.0 I have started to see decreased battery life. One of the main features ( or the main feature ) that I use is email. I have it connected to my main gmail account and my work Exchange account. Reading email always chewed through the battery but now it seems even worse.

We use a hosted Exchange provider which has been fairly good and trouble free and it's really nice to not have to maintain MS Exchange ( I used to be a sysadmin responsible for several Exchange boxes ).

Yesterday I received a notification email from our provider advising us of an ssue with iOS 4.0 with which Active sync no longer works correctly. While I didn't notice this at all ( an neither did any of the 7 other iPhone users in the office ) I followed through with the update. Unfortunately it didn't make a difference to the battery life and pretty much everyone else in the office is in the same boat.
Anyone else suffering and have any advice?

Official Apple article on the issue