I love my achilles. We have had him since 9/22/05. Quarantine is a must with these guys since they are so delicate. We battled ick, popeye, and some sort of swim bladder problem. But he is fantastic now! He has the coolest personality - he is like a golden retriever, when he sees me, he swims towards the glass and wags his tail fin. He will even eat out of my hand. An absolutely cool fish.
If you are going to get one, the key is to buy one that looks like its in good shape. Look for one that is dark in color - color is a good indicator of health in the Achilles, and most of the ones you will see in your LFS will be pale grey (not a good sign).
--Christy