I only had one ball with a TEC coverstock, a Complete Chaos, and it suffered TEC Death very quick. It lost almost all it's hooking power after about 60 games, and no matter what I did, it wouldn't come back.
Was originally drilled 4 x 5 when new, and hooked an absolute ton. After it died, I changed it to 4 1/2 x 3 3/8 and became a very nice down and in ball polished up. After the ball died, it actually became a lot more consistant, and didn't lose it's hitting power, just lost the ability to cover boards.
The ball is now retired for good, due to having no logos at all.
The covers seemed a little inconsistant from one to another, as I have seem some TEC balls just keep going and going and going. The are still a few Black Chaos's flying around here, that still hook almost as much as they did new.
They must have got lucky.