If anyone has had less than stellar results with Amdro, they might be using it incorrectly. I have found their instructions to be very accurate & if you do it wrong you will not see good results. You do NOT sprinkle it ON the nest you sprinkle it *around* the nest. I never get closer than 1" to the outer edge of their nest, most often 2" out from the outer edge. If you put it on their nest, they move. You need to do it in the morning. If you do it late in the day & the night dew falls upon the granules, then they won't finish taking it into the nest & you will find yourself with a still active nest you will have to re-treat.
I have tried other products claiming to kill fire ant nests and been sorely disappointed with them not to mention they are a pita to use. Amdro is super easy to use and it does the job.