This will be the third AC adpater I have had to purchase for my MacBook. The First one actually melted apart at the connector. The other ones just quit working a little more than a year after purchasing. Have not had the best experience with the Mag-Safe adapter. Love my Mac!
Its the power cord. How hard can it be?
The newer design with the metal angled connector seems to be a little better and much stronger, but still fails after a year.