Google has taken the new AdWords interface out of beta and now advertisers are being forced into the new interface, even though some don't want it.
A WebmasterWorld thread has one member who seems to not have the option to go back to the old interface after receiving an email from Google that says he will be switched any day now. The email read:
We're writing to let you know that your AdWords account (Customer Id: xx) will be upgraded to the new AdWords interface within the next few business days. After that time, you'll no longer be able to switch back to the previous AdWords interface to manage your campaigns. The new interface doesn't change how ads run, so bidding, ranking, Quality Score, and the rest of ad serving will remain the same after the upgrade...
One forum member suggested that this user try to force Google to give him the old interface by trying this URL and if that doesn't work, then go complain to your AdWords representative. There is actually a long and old thread that is an open plea to keep the old interface available, simply because some people like it better. When we polled our readers, 56% disliked the new interface.
Google has been testing this new interface since November 2008, then expanded the test in March 2009, then again in early April and late April and a bigger push in June. So this has been out there for a while, but many simply don't want it.
Forum discussion at WebmasterWorld.