The Avenue 6 is the pinnacle of controllers pre-dualshock.
You might as well say the pinnacle of all time then since certainly nothing good as been made post-Dual Shock. And as for that...I don't know. The ASCI SNES pad was f*cking great, as was the original Neo Geo AES stick, the Neo Geo CD pad, CP Solider (SNES version only) and the OG Saturn pad. Come to think of it, unless its an actual 6 button game, I prefer the standard PC Engine pad.
Frankly, the Dual Shock never did much for me. It has a solid feel and the analogs are really much nicer than the ones from other companies, but its kind of a cluttered mess. This is more of a problem with the controller spec for PS in general, but 15 years later I still can't remember the difference between "X" and "O" in a hurry. I actually don't have a huge problem with the goofy d-pad, but apparently everyone else does. Its a good controller for Gran Turismo or Metal Gear but not any good at all for fighting or shooters or Pac Man or the kind of stuff I play. In the same way, the Game Cube controller is really good too...for Game Cube native software.