Of course I'm still using them. Haven't yet got around to experimenting with different placement but that is because of being so happy with them right where they are.
We did have one interesting experience recently. A younger audiophile was here and when I played the XLO demagnetizing tracks and it got up into the highest frequencies it was hurting his ears. I couldn't hear a thing, but it was loud to him! I said we can always turn the supertweeters down if needed.
But then playing music he said it was fine. This to me jibes with the science that shows we have a lot of hearing cells devoted to very high ultra-sonic frequencies that are for time and transient information not sine waves. Hearing tests and measurements are all sine waves. Simplistic at best. Human beings don't hear that way and this backs that up. His ears found sine waves painful while the same super tweeter level with music was just fine.
They do improve imaging and the perception of "real" all across the audio band. Really fascinating stuff.