scout - 1:51 am on Feb 13, 2009 (gmt 0)
I agree - apples to apples ad copy testing is now almost impossible. New ads will often run in lower positions, so you can't compare CTR and conversions in a true test environment. Even if you modify, delete and re-add your existing ad, it will still get preferential treatment. I think you are now best off creating lots of multiple ads when you start a brand new ad group. After they run for awhile, throw out your underperforming ads and then leave the best ad alone for a long, long time.