Yes I did receive my MTR approval and it took exactly 2 years. My file went to the AAO on March 15, 2008 and it got approved on April 15th, 2010..so almost 2 years and 1 month more.. After the approval, my lawyer had to follow up with USCIS to get my I-140 approved on May 15th, 2010 as generally after AAO approval USCIS says that it may take 30 to 60 days to approve my I-140. Once that got approved my lawyer also had requested to re-instate my I-485 back and i got that re-instated on June 6th, 2010 and then filed for my EAD renewal soon after.
Don't worry you should be getting yr AAO approval soon and if not then ask your lawyer to follow up coz it does make a difference. Lawyers can appeal personally to USCIS.